Major storm cycle brings 4-8 ft of snow Jan 7-14!

[size=small](Note: Title edited to include dates.)[/size]

First major Pacific Northwest storm cycle of 2013-14 season to bring 4-8 ft of snow this week?

During the past 2 days, weather models have started predicting a major change in the weather pattern over the Pacific Northwest during the next week. The anomalously strong and persistent ridge of high pressure which has lingered just off the West Coast for much of the last 3 months may weaken and shift southward, allowing sustained westerly flow and a major winter storm cycle for the first time this season (at least since the exceptional late September 2013 storm cycle, which produced the most September snowfall in the Pacific Northwest since 1972).

The NWS's GFS model and the high-resolution UW WRF-GFS model which is built on it are showing up to 8-10" of precipitation over the next week, with snow levels generally in the 2000-4000 ft range. Snowfall during the next 3 days through 4pm Thursday is predicted to be 2-4 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics:



Higher resolution version of that, zoomed in on WA and OR:





There's a one-day lull predicted around Friday, then another sustained period of snowfall through Sunday. The model shows another 2-4 ft of snowfall over the Washington Cascades by Monday, with much lesser amounts for the Olympics and Oregon:




It will be be interesting to see whether the model's snowfall predictions for this week actually verify or not. The models could certainly be wrong, and the persistent ridge might continue to persist. But at least the models are predicting a major pattern change and sustained heavy snowfall for WA and OR, something which they have not really done thus far this season.

Hope so!

I'll believe it when I ski it.

THANKS---FINGERS CROSSED (AND TOES?).

That is welcome news.

awesome forecast at least, not news yet.
b

It will undoubtedly snow 2-3 feet Friday night/ Saturday morning as I plan on watching the Seahawks game Saturday and not heading up until Sunday. You guys are welcome.

Update: 24 hours later, models are still predicting 4-8 ft (or more) of snow this week

A day later, and 2 subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for large snowfall amounts. Consistency between subsequent model runs typically tends to indicate that the predictions are more likely to actually verify.

Snowfall during the next 3 days through 4am Friday is still predicted to be 2-4 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics:



Higher resolution version of that, zoomed in on WA and OR:





There's still a one-day lull predicted around Thursday evening into early Friday, then another sustained period of snowfall through Sunday. This second part of the storm cycle now looks to be much stronger and wetter, with much more snowfall predicted over the weekend and extending much farther south into Oregon too. The model now shows another 2-6 ft of snowfall over the Washington Cascades by Monday, with 2-3 ft for the Olympics and Oregon:

Thanks for the info! NOAA says rain/snow on Friday night at Snoqualmie Pass (~5k').

Does the UW model agree, or does it predict that temps will stay low until Saturday?

Thanks for the info!  NOAA says rain/snow on Friday night at Snoqualmie Pass (~5k'). 

Does the UW model agree, or does it predict that temps will stay low until Saturday?

You can see for yourself with the 12km 5000' elevation temperatures:

Here's the GFS ("more precise"):
www.atmos.washington.edu/~ovens/wxloop.c..._wa_5000_snow+//84/3

Here's the NAM (more current, the GFS hasn't yet run since this morning)
www.atmos.washington.edu/~ovens/wxloop.c..._wa_5000_snow+//72/3

Both show freezing levels above 5k at Snoqualmie on Friday evening.

Saturday afternoon/night is when the temps really drop in the current runs and Snoqualmie will see some accumulation... but that's still a five day, I'll start trusting it more when the 4km run can see the event.

Andy

Update #2: 48 hours after initial post, models are still predicting 4-8 ft (or more) of snow this week

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for large snowfall amounts. There is definitely consistency between subsequent model runs through the weekend (still 5 days out at this point), which typically tends to indicate that the predictions are more likely to actually verify.

Up to 6" of new snow has already fallen as of Wednesday morning, with the largest amounts on Mounts Rainier, Hood, and Bachelor thus far. Additional snowfall during the next 2 days through 4am Friday is predicted to be 1-3 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics:



Higher resolution version of that, zoomed in on WA and OR:





There's now a lull predicted around Thursday morning and again Friday morning with a brief period of precip in between, then another sustained period of snowfall from Friday afternoon through Sunday. This second part of the storm cycle continues to look much stronger and wetter than it did 2 days ago, with much more snowfall predicted over the weekend and extending much farther south into Oregon too. The model still shows another 2-6 ft of snowfall over the Washington Cascades during the 3-day period through 4am Monday, with 2-3 ft for the Olympics and Oregon:



This loop shows how the model predictions for snowfall during the 3-day period through 4am Friday have evolved between subsequent runs, known in the jargon as D(model)/D(t):
www.atmos.washington.edu/~ovens/wxloop.c...2+v2014011012///+-st

And similarly for the 3-day period through 4am Monday:
www.atmos.washington.edu/~ovens/wxloop.c...2+v2014011312///+-st

The model is showing some additional snowfall during Monday as this storm cycle fades out, but only about 4-8" in the WA Cascades with very little in the Olympics and Oregon.

And although this storm cycle now appears nearly-certain to boost snowdepths substantially in WA and OR, it will do little to help California, with only a few inches of new snow forecast to extend south as far as Lake Tahoe during the most intense part of the system on Saturday. The snowpack may be abnormally low in the Pacific Northwest now, but the situation in California is far more dire: there is almost no snow on the ground at all in the mountains, with less than 1 foot of snowpack throughout the California Cascades and Sierra Nevada, as many sites even at elevations above 7000 ft are reporting zero snow or only a few inches. Mount Shasta is almost completely bare of snow except the glaciers on the north and east sides, as is Lassen Peak on all sides (normally, Lassen is by far the snowiest location in California):





Just shocking images for early January! This is the third consecutive season where the California snowpack has been far below normal, and no relief appears to be on the horizon for that region in any forecast or outlook yet.

southern california is just growing, no big deal.
b

Maybe those snowless photos from California are just too depressing. Thankfully, it's currently snowing over a 600+ mile stretch of the Pacific Northwest mountains, extending from the Coast Mountains and BC Cascades, through the Olympics, Washington Cascades, and Oregon Cascades as far south as Crater Lake. Here are some much nicer SNOWY webcam images from today across that entire length:

BC:

Whistler Peak, 7150 ft:


Whistler Olympic Park, in Callaghan Valley near Mt Cayley, 2800 ft:


Mt Garibaldi, Brohm Ridge, 4900 ft:



WA:

Olympics, Hurricane Ridge, 5250 ft:


Stevens Pass, 4100 ft:


Snoqualmie Pass, 3000 ft:


Crystal Mtn, Gold Hills, 5000 ft:


Mt Rainier, Paradise, 5400 ft:


White Pass, 4500 ft:



OR:

Mt Hood, Timberline Lodge, 5900 ft:


Mt Hood Meadows, 5250 ft:


Santiam Pass, 4800 ft:


Mt Bachelor, West Village, 6350 ft:


Crater Lake, Rim Village, 7100 ft:

Update #3: 72 hours after initial post, models are still predicting totals of 4-8 ft (or more) of snow this week

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for large snowfall amounts through the weekend. The higher-resolution 4 km model runs now cover the period through Sunday evening, and the consistency between subsequent runs means that it is very likely that the second heavier portion of this storm cycle will actually occur as predicted.

About 1-2 ft of new snow has already fallen as of Thursday morning, with the largest amounts on Mounts Baker, Rainier, Hood, and Bachelor thus far, but even Snoqualmie Pass has received about 1 ft of new snowfall, almost doubling the current snowdepth there at pass level. There was a lull between systems after midnight last night, but the next front is already upon us for additional snowfall into Friday morning, followed by another partial lull and then another sustained period of very heavy precip and snowfall from Friday afternoon through Sunday. Heavy rain may fall up to 6000-7000 ft Friday night, but snow levels should rapidly lower by Saturday morning with heavy snowfall throughout the day and on Sunday.

Additional snowfall during the next 3 days through 4am Sunday is predicted to be 2-4 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics (note the shift in time period compared to graphics shown in previous posts above):



Higher resolution version of that, zoomed in on WA and OR:





The model shows another 2-4 ft of snowfall over the northern Washington Cascades over the next 3 day period though 4am Wednesday, the bulk of it falling on Sunday night and Monday, with much lesser amounts for the Olympics, southern Washington, and Oregon:



The real jackpot for this period appears to be the central BC Coast Mountains, roughly from the Homathko Icefield and the Waddington Range northwestward through Silverthrone Mountain and the Ha-iltzuk Icefield, with another 4-8 ft of snowfall over those 3 days. That region has probably received the most precip and snowfall of any part of the West Coast of North America during the last few months, even more than areas farther north like southeast Alaska and south-central Alaska. The persistent ridge of high pressure off the US West Coast has tended to push system after system directly into that portion of the BC Coast Mountains over the last 3 months, instead of allowing a large fraction of them to hit WA and OR as they normally would. Mountain snowpack in that region must be very deep already and well above normal, but unfortunately there are no snow measurement sites of any kind in that entire region, with the exception of two BC RFC snow telemetry sites (3A22P & 3A24P) located in the extremely rain-shadowed, low-snowfall region NE of the Homathko and Waddington ranges -- they barely record any snowpack even in normal years and are not at all representative of the snowpack along the crest of the mountains. That region is the most remote and least inhabited (not to mention the highest and most heavily glaciated) section of the entire BC Coast Mountains, with no roads at all crossing the range over the 250 mile stretch from Whistler (Hwy 99) to Bella Coola (Hwy 20), and no way to accurately know how much snowpack has accumulated up there this year, nor even what normal snowpack values might be.

The NWS forecast finally started agreeing with this model little more than a day ago - but then, it hasn't played out yet..   The wind map   put up a couple weeks ago shows how BC is getting hammered.  Still no love for the Sierra - actually it's getting serious from the San Joaquin through the Great Basin.

Update #4: 96 hours after initial post, models are still predicting totals of 4-8 ft (or more) of snow this week -- and they've been accurate so far!

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for large snowfall amounts through the weekend. The higher-resolution 4 km model runs now cover the period through Monday evening, so basically to the end of the storm cycle, and ongoing consistency between subsequent runs means that it is very likely that the second heavier portion of this storm cycle will actually occur as predicted this weekend.

About 1-3 ft of new snow has already fallen during the 3 days since the storm cycle began early Tuesday, January 7, through Friday morning, with the largest amounts on Mounts Baker, Rainier, Hood, and Bachelor thus far, but even Snoqualmie Pass has received about 16" of new snowfall (with over 2 ft at the top of Alpental), almost doubling the previous snowdepth there at pass level. Total precip through noon Friday has been about 2.5" at Baker and Stevens, 3.5" at Snoqualmie, 3" at Paradise, 2" at White Pass, 4" at Mount Hood Meadows, and over 5" at Timberline on Hood. Snowfall amounts of over 4 ft were likely received at 7000 ft on Hood where the precip remained entirely snow, versus periods of mixed precip and extremely dense wet snowfall at Meadows and Timberline.

So the initial model predictions, for snowfall amounts up to 2-4 ft during the first 3 days of the storm cycle over the west slopes and volcanic peaks of the Washington and Oregon Cascades, have largely been verified. The persistent ridge did flatten and shift south, opening the door for westerly flow, and the expected frontal systems did come through as forecast with snow levels in the 2000-4000 ft range (4000-6000 ft in Oregon) as expected, with precipitation and snow totals roughly matching the predicted amounts. Substantial success thus far for the weather models! It's quite remarkable how much this type of numerical weather prediction has improved over even just the last decade.

There is another partial lull between systems now during the day Friday, followed by a warm front this afternoon and then another sustained period of very heavy precip and snowfall from Friday afternoon through Sunday. Heavy rain may fall up to 6000-7000 ft Friday night, but snow levels should rapidly lower by Saturday morning with heavy snowfall throughout the day and on Sunday.

Additional snowfall during the next 3 days through 4am Monday is predicted to be 2-6 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics (note another 24-hour shift in time period compared to graphics shown in update #3 above):



Higher resolution version of that, zoomed in on WA and OR:




This loop shows how the model predictions for snowfall during the 3-day period through 4am Monday have evolved between 10 subsequent runs over the last 5 days, known in the jargon as D(model)/D(t). Slight changes in the details, but very consistent in the overall picture and maximum snowfall amounts:
www.atmos.washington.edu/~ovens/wxloop.c...2+v2014011312///+-st


The model shows another 6-12" of snowfall over the northern Washington Cascades over the next 3 day period though 4am Thursday, almost all of it falling on Monday, with barely 1-2" more for the Olympics, southern Washington, and Oregon:



Unfortunately it looks like the persistent ridge of high pressure off the West Coast will rebuild northward during the early part of next week, bringing this storm cycle to an end. Details beyond that point are murky and very uncertain as of now.

The broad overview of the 36 km domain provides a nice picture of today's incoming system, and the rebuilding ridge at the start of next week, especially using the 700 mb temperature, winds, heights loop. Here are some annotated frames from that loop:
www.atmos.washington.edu/~ovens/wxloop.c..._700t+2014011012///3

Now, 1pm Friday, strong low pressure system well off the coast, with leading warm front crossing the WA Cascades:


7am Saturday, strong low pressure system just off the tip of Vancouver Island, with trailing cold front crossing the WA Cascades, and snow levels plummeting:


7am Sunday, strong post-frontal WNW flow produces heavy orographic snowfall throughout Saturday and into Sunday for WA and OR Cascades:


7am Monday, the ridge is rebuilding off the coast, but precip continues to flow over the north end of it into WA, at rising snow levels:


7am Tuesday, the rebuilding ridge is shifting east onto the coast, and precip is now being deflected far to the north into the central BC coast:


7am Wednesday, strong ridge still in place over the US West Coast:

Another slow day at the office?

Another slow day at the office?

Apparently. Almost went to Crystal, but bailed at 6am after it barely got any snow overnight and I barely got any sleep.  Even if I had skied, I probably would have posted the same update after I got home this evening. Maybe I should have gone, it looked nice and sunny up there for a couple hours before it socked in.

Super thankful for all the new snow. Unfortunately, I'm mired in real world responsibility this weekend. I'll have to live vicariously through the bevy of reports that are sure to appear. Unfortunately, the extended forecast looks a mess with high freezing levels and rain. Lots of snow and wind followed by a significant warm up and rain...hmm...stay safe out there this weekend and next week.

Unfortunately, the extended forecast looks a mess with high freezing levels and rain.  Lots of snow and wind followed by a significant warm up and rain...hmm...stay safe out there this weekend and next week.

I'm curious as to which extended forecast you looked at which showed that (high freezing levels and rain), and how far out in the future -- I'm not really seeing that in the models I've looked at, extending out 1 week (or even in the low-resolution extended GFS out to 16 days -- although model predictions beyond about 7 days have little forecast skill and are not reliable). This storm cycle is predicted to conclude with only a modest rise in snow levels at its tail end on Monday, followed by a period of mostly sunny warm weather during the upcoming week (Tues-Fri, especially south) as the persistent ridge rebuilds once again.

Update #5: 120 hours after initial post, models are still predicting totals of 4-8 ft (or more) of snow this week -- and they've been accurate so far!

"Everything is proceeding as I have foreseen..."
[size=small] -- UW WRF-GFS Model[/size]

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for large snowfall amounts through the rest of this weekend. This storm cycle has proceeded largely as predicted several days prior to its start by the models, and it is reasonable to expect that predictions over the remaining 2-3 days of the event will continue to be as accurate.

About 1-4 ft of new snow has already fallen during the 4 days since the storm cycle began early Tuesday, January 7, through Saturday morning, with the largest amounts on Mounts Baker, Rainier, Hood, and Bachelor thus far, but even Snoqualmie Pass has received about 16" of new snowfall (with nearly 3 ft at the top of Alpental), almost doubling the previous snowdepth there at pass level. Total precip through mid-morning Saturday has been over 5" at Baker, about 2" at Hurricane Ridge (mostly rain) and Washington Pass (almost all snow), 4" at Stevens, almost 5" at Snoqualmie, 1.5" at Crystal, over 4" at Paradise, 2.5" at White Pass, almost 5" at Mount Hood Meadows, and over 6" at Timberline on Hood. Snowfall amounts of about 5 ft were likely received above 7000 ft on Hood where the precip remained entirely snow, versus periods of mixed precip and extremely dense wet snowfall at Meadows and Timberline.

The strongest system of this storm cycle arrived Friday afternoon into Saturday. The strong leading warm front passed through on Friday afternoon, with heavy rain falling up to 6000-7000 ft Friday night as predicted, and then the strong trailing cold front passed through during the early hours of Saturday before sunrise, lowering snow levels dramatically to about 3000 ft. After a partial reduction in precip intensity this morning, heavy snowfall is expected above 2-3000 ft throughout the rest of Saturday and on Sunday.

Additional snowfall during the next 3 days through 4am Tuesday is predicted to be 2-4 ft over the west slopes and volcanic peaks of the Washington and Oregon Cascades, plus the Olympics (note another 24-hour shift in time period compared to graphics shown in update #4 above):



Higher resolution version of that, zoomed in on WA and OR:




Almost all of that snowfall will have fallen before Monday morning. During the last 24 hours of that period on Monday, the model still shows another 6-12" of snowfall over the northern Washington Cascades with snow levels rising to about 4000 ft, with barely a few inches more for the Olympics and southern Washington, and almost nothing in Oregon:




It still looks nearly-certain that the persistent ridge of high pressure off the West Coast will rebuild northward during the early part of next week, bringing this storm cycle to an end. However, it should also bring several days of mostly sunny warm weather during the upcoming week, mainly Tuesday-Friday and especially south, which may be ideal conditions for ski mountaineering on above-treeline, avy-safe terrain on the volcanoes.

Details beyond that point are murky and very uncertain as of now, but the extended GFS model does predict another major pattern change during the 7-16 day time frame. The stubbornly persistent West Coast ridge shifts eastward and merges with a large ridge over the middle part of North America, opening the door to further systems and precipitation to reach the Pacific Northwest. That persistent ridge off the West Coast appears to be gone by 2 weeks from now, although another ridge could always rebuild in a similar location. Take those 7-16 day predictions with a large grain of salt, because as mentioned in the previous post, model predictions beyond about 7 days have little forecast skill and are not reliable.

I'm curious as to which extended forecast you looked at which showed that (high freezing levels and rain), and how far out in the future -- I'm not really seeing that in the models I've looked at, extending out 1 week (or even in the low-resolution extended GFS out to 16 days -- although model predictions beyond about 7 days have little forecast skill and are not reliable). This storm cycle is predicted to conclude with only a modest rise in snow levels at its tail end on Monday, followed by a period of mostly sunny warm weather during the upcoming week (Tues-Fri, especially south) as the persistent ridge rebuilds once again.

I have read this thread with much interest, as I have learned a lot. I will admit to having an infinitesimal understanding of weather prediction and rely heavily on the work of others. Last night I took a very quick look at NOAA and the Rec forecast. My quick skim saw rain and rising freezing levels. The current reports call for more sun and possible showers.

Update #6: 144 hours after initial post, models predictions have verified with snow totals of 3-7 ft already -- and more still falling!

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show similar predictions for ongoing snowfall through the rest of this weekend. This storm cycle has proceeded largely as predicted several days prior to its start by the models, and it really is a stunning success that weather models could quite accurately predict this event from 5-7 days out, including reasonably correct snowfall amounts. Forecasting precip amounts accurately is quite difficult (much more so than temperature or wind), and doing so for snowfall amounts is even more difficult.

The strongest system of this storm cycle arrived Friday afternoon into Saturday, with heavy precip and snowfall. The strong leading warm front passed through on Friday afternoon, with heavy rain falling up to 6000-7000 ft (except 4500-5000 ft in northernmost WA and southwest BC) on Friday night as predicted, and then the strong trailing cold front passed through during the early hours of Saturday before sunrise, lowering snow levels dramatically to about 3000 ft with heavy snowfall throughout the rest of Saturday. On Saturday afternoon for a few hours, snowfall from this single system extended over an 1100-mile stretch (as the crow flies, or 1500+ miles by car ) of the West Coast from the mountains near Bella Coola, BC, to Mammoth Mountain, CA, in the eastern Sierra Nevada (although snowfall amounts were barely a few inches anywhere in California). A very extensive storm system!

Higher elevation sites in northernmost Washington and southwest BC that remained all snow during the warm portion of the system received 2-3 ft of snowfall in 24 hours by Saturday evening. Whistler Mountain reported 19" new at their 5400 ft snowfall plot on Saturday morning and 25" by Saturday afternoon (after getting only a few inches during the first 3 days of the storm cycle), although it was mostly rain lower down and in the Village. The nearby Squamish River BCRFC site stayed all snow despite its modest 4500 ft elevation, and got 3 ft of new snow. The Chilliwack River BCRFC site at 5300 ft in the BC Cascades just north of the US border near Mount Baker became the first telemetry site in the Cascades to reach 100" of snowdepth (and the first in North America as far as I know) on Saturday afternoon, followed a few hours later by the Brown Top SNOTEL site at 5800 ft near Mount Redoubt in the North Cascades, which also got almost 3 ft in 24 hours:

[size=small]SQUAMISH RIVER (UPPER)   1387 m (4550 ft)
Located 45 km (28 miles) NW of Mt Garibaldi
    and 11 km (7 miles) WNW of Mt Cayley

Date         Time      Temp     Rain Gauge     SWE        Snowdepth
            (PST)   (°C)  (°F)  (mm)  (in)  (mm)  (in)   (cm)  (in)

---

2014-01-10  16:00   -3.0  26.6   898  35.4   394  15.5   146   57.5
2014-01-10  17:00   -3.3  26.1   899  35.4   395  15.6   147   57.9
2014-01-10  18:00   -3.5  25.7   900  35.4   397  15.6   148   58.3
2014-01-10  19:00   -3.6  25.5   901  35.5   398  15.7   149   58.7
2014-01-10  20:00   -3.7  25.3   903  35.6   403  15.9   775  305.1
2014-01-10  21:00   -3.6  25.5   907  35.7   411  16.2   156   61.4
2014-01-10  22:00   -3.5  25.7   911  35.9   418  16.5   158   62.2
2014-01-10  23:00   -3.5  25.7   915  36.0   427  16.8   162   63.8

---

2014-01-11  00:00   -3.5  25.7   919  36.2   434  17.1   168   66.1
2014-01-11  01:00   -3.6  25.5   924  36.4   443  17.4   172   67.7
2014-01-11  02:00   -3.3  26.1   930  36.6   451  17.8   178   70.1
2014-01-11  03:00   -2.8  27.0   937  36.9   459  18.1   186   73.2
2014-01-11  04:00   -1.9  28.6   942  37.1   464  18.3   182   71.7
2014-01-11  05:00   -1.4  29.5   946  37.2   467  18.4   775  305.1
2014-01-11  06:00   -1.5  29.3   947  37.3   468  18.4   775  305.1
2014-01-11  07:00   -1.6  29.1   947  37.3   469  18.5   189   74.4
2014-01-11  08:00   -2.5  27.5   948  37.3   470  18.5   191   75.2
2014-01-11  09:00   -2.5  27.5   948  37.3   470  18.5   185   72.8
2014-01-11  10:00   -2.6  27.3   948  37.3   472  18.6   775  305.1
2014-01-11  11:00   -2.9  26.8   950  37.4   477  18.8   191   75.2
2014-01-11  12:00   -2.9  26.8   954  37.6   482  19.0   200   78.7
2014-01-11  13:00   -2.7  27.1   957  37.7   486  19.1   207   81.5
2014-01-11  14:00   -2.6  27.3   959  37.8   488  19.2   202   79.5
2014-01-11  15:00   -2.6  27.3   961  37.8   489  19.3   210   82.7
2014-01-11  16:00   -2.8  27.0   962  37.9   491  19.3   212   83.5 <<< 26" snowdepth increase in 24 hours,
2014-01-11  17:00   -3.0  26.6   963  37.9   492  19.4   208   81.9     along with 3.8" SWE increase, implies
2014-01-11  18:00   -2.8  27.0   964  38.0   493  19.4   211   83.1     24 hour snowfall of about 3 ft !
2014-01-11  19:00   -3.2  26.2   964  38.0   493  19.4   210   82.7
2014-01-11  20:00   -3.4  25.9   964  38.0   493  19.4   208   81.9
2014-01-11  21:00   -4.4  24.1   964  38.0   493  19.4   209   82.3
2014-01-11  22:00   -3.9  25.0   964  38.0   493  19.4   208   81.9
2014-01-11  23:00   -3.9  25.0   964  38.0   493  19.4   207   81.5

---

CHILLIWACK RIVER   1621 m (5320 ft)
Located 29 km (18 miles) NNE of Mt Baker
    and 4 km (2.5 miles) north of US border

Date         Time      Temp     Rain Gauge     SWE        Snowdepth
            (PST)   (°C)  (°F)  (mm)  (in)  (mm)  (in)   (cm)  (in)

---

2014-01-10  16:00   -3.7  25.3  1083  42.6   791  31.1   231   90.9
2014-01-10  17:00   -3.8  25.2  1083  42.6   793  31.2   232   91.3
2014-01-10  18:00   -3.5  25.7  1083  42.6   797  31.4   231   90.9
2014-01-10  19:00   -2.9  26.8  1082  42.6   799  31.5   234   92.1
2014-01-10  20:00   -2.5  27.5  1084  42.7   802  31.6   235   92.5
2014-01-10  21:00   -2.1  28.2  1083  42.6   805  31.7   236   92.9
2014-01-10  22:00   -1.1  30.0  1086  42.8   808  31.8   239   94.1
2014-01-10  23:00   -0.5  31.1  1086  42.8   814  32.0   239   94.1

---

2014-01-11  00:00    0.0  32.0  1084  42.7   819  32.2   239   94.1
2014-01-11  01:00    0.0  32.0  1086  42.8   822  32.4   239   94.1
2014-01-11  02:00    0.0  32.0  1091  43.0   827  32.6   240   94.5
2014-01-11  03:00    0.0  32.0  1111  43.7   832  32.8   239   94.1
2014-01-11  04:00    0.0  32.0  1112  43.8   836  32.9   241   94.9
2014-01-11  05:00    0.0  32.0  1112  43.8   842  33.1   242   95.3
2014-01-11  06:00   -1.9  28.6  1110  43.7   848  33.4   245   96.5
2014-01-11  07:00   -2.9  26.8  1110  43.7   854  33.6   540  212.6
2014-01-11  08:00   -3.1  26.4  1112  43.8   856  33.7   540  212.6
2014-01-11  09:00   -3.1  26.4  1112  43.8   859  33.8   540  212.6
2014-01-11  10:00   -3.2  26.2  1112  43.8   862  33.9   540  212.6
2014-01-11  11:00   -3.2  26.2  1112  43.8   864  34.0   251   98.8
2014-01-11  12:00   -3.0  26.6  1113  43.8   867  34.1   251   98.8
2014-01-11  13:00   -2.7  27.1  1114  43.9   868  34.2   251   98.8
2014-01-11  14:00   -3.1  26.4  1114  43.9   871  34.3   252   99.2
2014-01-11  15:00   -3.4  25.9  1114  43.9   872  34.3   252   99.2
2014-01-11  16:00   -3.4  25.9  1114  43.9   872  34.3   254  100.0 <<< first telemetry site in Cascades
2014-01-11  17:00   -3.6  25.5  1114  43.9   874  34.4   255  100.4     to reach 100" snowdepth (and first
2014-01-11  18:00   -3.8  25.2  1116  43.9   877  34.5   260  102.4     in North America as far as I know)
2014-01-11  19:00   -3.7  25.3  1116  43.9   880  34.6   263  103.5
2014-01-11  20:00   -3.7  25.3  1117  44.0   882  34.7   265  104.3
2014-01-11  21:00   -3.8  25.2  1116  43.9   883  34.8   266  104.7
2014-01-11  22:00   -4.4  24.1  1116  43.9   884  34.8   267  105.1
2014-01-11  23:00   -5.2  22.6  1112  43.8   888  35.0   266  104.7

---

BROWN TOP SNOTEL   5830 ft
Located 15 miles north of Diablo, 5 miles south of Canadian border

                    Snow       Precip
                   Water  Snow  since   Air  Wind  Wind Wind
     Date / Time   Equiv Depth  Oct 1  Temp   Avg   Max  Dir
           (PST)    (in)  (in)   (in)  (°F) (mph) (mph)  (°)

---

2014-01-10 20:00    22.9    80   20.2    28   4.6   6.8  210
2014-01-10 21:00    23.0    80   20.2    29   4.6   8.5  213
2014-01-10 22:00    23.2    81   20.3    31   4.7   7.8  174
2014-01-10 23:00    23.3    81   20.4    32   4.1   9.8  230

---

2014-01-11 00:00    23.4    82   20.4    32   5.6  13.5  239
2014-01-11 01:00    23.5    82   20.5    33   5.6  11.6  181
2014-01-11 02:00    23.8         20.6    33   5.9  16.2  229
2014-01-11 03:00    23.9    85   20.8    34   5.5  13.5  240
2014-01-11 04:00    24.0         20.7    33   4.2  12.5  185
2014-01-11 05:00    24.2         20.8    33   4.3   9.0  152
2014-01-11 06:00    24.4    89   20.9    32   4.9   9.6  250
2014-01-11 07:00    24.7    89   21.5    30   8.2  14.3  212
2014-01-11 08:00    24.9    93   21.6    28   9.9  17.1  254
2014-01-11 09:00    25.0    91   21.6    28   8.1  13.4  241
2014-01-11 10:00    25.2         21.8    27   6.7  15.5  184
2014-01-11 11:00    25.2    91   21.8    27   4.8  12.5  137
2014-01-11 12:00    25.3    91   21.8    27   3.0   6.7  144
2014-01-11 13:00    25.5    96   21.9    27   2.8   5.9  130
2014-01-11 14:00    25.6    94   22.0    27   4.0   8.1  210
2014-01-11 15:00    25.8    96   22.1    26   2.6   7.1  218
2014-01-11 16:00    25.8    96   22.1    26   4.1  10.8  235
2014-01-11 17:00    26.0    98   22.2    26   2.8   9.4  208
2014-01-11 18:00    26.1    99   22.2    26   7.9  13.8  127
2014-01-11 19:00    26.2   101   22.2    26   6.2  11.7  241 <<< second telemetry site in Cascades
2014-01-11 20:00    26.4   101   22.4    26   3.8   9.9  258     to reach 100" snowdepth
2014-01-11 21:00    26.5   102   22.5    26   4.0   9.5  254
2014-01-11 22:00    26.6   103   22.6    26   3.6   8.0  244 <<< 23" snowdepth increase in 24 hours,
2014-01-11 23:00    26.6   101   22.6    25   4.8  10.6  262     along with 3.7" SWE increase, implies

---

     24 hour snowfall of almost 3 ft !

(The Flattop Mountain SNOTEL site at 6300 ft in Montana also reached 100" on Sunday morning due to this same storm cycle,
the first site outside the Cascades to do so, as far as I know -- there may be some other sites that I have missed.)[/size]


The last portion of the storm cycle is now underway on Sunday, starting with a period of extremely intense snowfall Sunday morning -- the climax of this entire storm cycle. Especially from the central WA Cascades south to the northern OR Cascades, snowfall rates of 2-4" per hour early Sunday morning produced another 6-12" of snow in only 4-5 hours at many sites, with 24 hour totals of 2 ft at many sites. Snow levels remained low at 2000-3000 ft during that intense snowburst, but are rising to 4000-5000 ft as another warm front approaches.

About 3-7 ft of new snow has already fallen during the 5 days since the storm cycle began early Tuesday, January 7. Total snowfall through mid-day Sunday has been about 3 ft at Whistler Mountain, 4.5 ft at Baker Ski Area, over 5 ft at Brown Top SNOTEL, 3 ft at Buckinghorse SNOTEL in the Olympics, about 1.5 ft at Hurricane Ridge, over 3 ft at Washington Pass, almost 4 ft at Stevens, barely 1 ft at Mission Ridge, 2.5 ft at Snoqualmie (almost tripling the previous snowdepth there at pass level) with about 4.5 ft at the top of Alpental, 2 ft at Crystal Mountain base with over 3 ft in Green Valley, 5 ft at Paradise, almost 4 ft at the top of White Pass, about 3 ft at 4000 ft on Mount Saint Helens, over 4 ft at Timberline and Mount Hood Meadows, and 3.5 ft at Mount Bachelor. Snowfall totals diminish rapidly farther south in Oregon, with about 2 ft at Willamette Pass and Crater Lake, and only about 1 ft at Mount McLoughlin, then truly plummet in California, with only about 2-5" new (all of which fell on Saturday) for Mount Shasta, Lassen Peak, and the Sierra Nevada.

Total precip through mid-day Sunday has been about 7" at Baker Ski Area and Brown Top SNOTEL, 9" at Buckinghorse SNOTEL in the Olympics, 3.5" at Hurricane Ridge (half rain) and Washington Pass (almost all snow), over 5.5" at Stevens, under 1.5" at Mission Ridge, about 7.5" at Snoqualmie, 3" at Crystal, 6.5" at Paradise, almost 5" at White Pass, about 9-11" on Mount Saint Helens, over 8" at Mount Hood Meadows, and almost 10" at Timberline on Hood. Given those precip amounts, snowfall totals of over 7 ft were likely received above 7000 ft on Mount Hood where the precip remained entirely snow, versus periods of mixed precip and extremely dense wet snowfall at Meadows and Timberline.

Snowdepths have increased substantially at most measurement sites in the Cascades and Olympics, doubling or even tripling at many sites especially at lower elevations and in Oregon. Snowdepth at Paradise broke 100" on Sunday morning, a very significant number since Paradise has reached 100" in every season except 2004-2005 when it maxed out at 95" (manual snowdepth records extend back to 1916 at Paradise, with only 3 missing years). Even in that year, the NWAC Paradise telemetry site may have topped 100" for about 20 hours on April 15-16, but the depth sensor had been very flaky throughout that spring, randomly fluctuating by 15-20", making the correct values uncertain. Snowdepth at Paradise is now roughly 100% of normal for this date! -- it's kind of shocking to see that, given how far below normal this season has been thus far (of course, obviously the new snowfall will rapidly settle and reduce the depth below 100% of normal in a few days -- but January snowdepth values often include much new unconsolidated snow like this). All other sites in the Cascades, Olympics, and southwest BC remain below 100% of normal snowdepth, but a few others are close especially farther north: Whistler Mountain, Baker Ski Area, and Stevens Pass are all roughly 90% of normal as of now.

One big Pacific Northwest storm cycle can really fix a low snowpack! And this was merely a big storm cycle, not a huge one at all -- huge Northwest storm cycles can deliver 10-15 ft of snow during 1 week.

Additional snowfall during the 2 day period through 4am Tuesday is predicted to be 2-4 ft over the northern Washington Cascades (an increase from earlier predictions), with 1-2 ft for the southern Washington and Oregon Cascades, plus the west slopes of the Olympics (note the reduction in time period compared to graphics shown in update #5 above):



Higher resolution version of that, zoomed in on WA and OR:




Almost all of that snowfall will have fallen before Monday morning, except in the North Cascades. During the last 24 hours of that period on Monday, the model now shows another 6-24" of snowfall over the northern Washington Cascades with snow levels rising to above 4000 ft, with barely a few inches more for the Olympics and southern Washington, and almost nothing in Oregon:




The persistent ridge of high pressure off the West Coast will rebuild northward during the early part of next week, bringing this storm cycle to an end. However, it should also bring several days of mostly sunny warm weather during the upcoming week, mainly Tuesday-Friday and especially south -- probably ideal conditions for ski mountaineering on above-treeline, avy-safe terrain on the volcanoes.

Details beyond that point remain murky and very uncertain as of now, with subsequent runs of the extended GFS model shifting around predictions during the 7-16 day time frame. Best to wait a few more days until the high pressure rebuilds midweek, to see if models become more consistent in their predictions for the week after that.

Some snippets of NWAC telemetry showing the extreme snowfall intensity on Sunday morning, with the climactic snowburst marked with **:

[size=small]Northwest Avalanche Center
Stevens Pass Ski Area Brooks Chair (4850')
Washington Department of Transportation Schmidt Haus (3950')
Stevens Pass, Washington

MM/DD Hour Temp Temp RH RH Wind Wind Wind Hour Total 24 Hr Total Press
PST F F % % Avg Max Dir Prec Prec Snow Snow mb
4850' 3950' 4850' 3950' 4850' 4850' 4850' 3950' 3950' 3950' 3950' 3950'

---

1 12 100 24 29 100 91 15 52 222 .06 .98 14 59 1005
1 12 200 24 29 100 87 14 39 224 .01 .99 14 59 1005
1 12 300 24 28 100 91 16 52 222 .05 1.04 15 59 1007
1 12 400 24 28 100 88 15 45 227 .02 1.06 15 59 1009
1 12 500 24 28 100 92 14 38 221 .04 1.1 15 59 1009
1 12 600 24 28 100 96 11 35 224 .12 1.22 1 61 1010 **
1 12 700 24 28 100 95 9 25 220 .1 1.32 2 62 1011 **
1 12 800 25 29 100 95 8 21 225 .07 1.39 4 63 1012 **
1 12 900 25 29 100 95 6 20 239 .08 1.47 6 65 1012 **
1 12 1000 26 30 100 94 7 18 228 .06 1.53 5 65 1012
1 12 1100 28 31 100 94 9 21 232 .03 1.56 8 65 1013
1 12 1200 30 32 100 94 9 23 229 .05 1.61 7 65 1013
1 12 1300 30 33 100 94 7 18 221 .07 1.68 8 66 1013
1 12 1400 30 33 100 94 8 18 219 .08 1.66 9 67 1014


Northwest Avalanche Center
Washington Department of Transportation
Grace Lakes, Stevens Pass, Washington

Shot Snow not yet installed for winter season
Prec gage occasionally malfunctioning

MM/DD Hour Temp RH Wind Wind Wind Hour Total Total Shot
PST F % Avg Max Dir Prec Prec Snow Snow
4800' 4800' 4800' 4800' 4800' 4800' 4800' 4800' 4800'

---

1 12 100 25 97 7 32 231 0 0 79
1 12 200 25 97 7 18 235 0 0 78
1 12 300 25 97 7 22 230 0 0 78
1 12 400 24 97 6 27 231 0 0 76
1 12 500 25 97 6 20 228 0 0 77
1 12 600 25 97 6 23 237 0 0 80 **
1 12 700 25 97 7 21 236 0 0 83 **
1 12 800 25 97 4 18 223 0 0 85 **
1 12 900 26 98 1 5 98 0 0 88 **
1 12 1000 27 98 3 9 202 0 0 89 ** 12" new in 5 hours!
1 12 1100 29 99 3 11 212 0 0 86
1 12 1200 31 100 4 13 209 0 0 87
1 12 1300 31 100 3 10 199 0 0 91
1 12 1400 31 100 4 12 224 0 0 91


Northwest Avalanche Center
Alpental Ski Area, Washington

Wind gages unheated and may rime
New mid-station installed early Dec
Data not available until new IP address approved by NWS/NOAA

MM/DD Hour Temp Temp Temp RH RH Wind Wind Wind Hour Total 24 Hr Total 24 Hr
PST F F F % % Avg Max Dir. Prec Prec Snow Snow Snow
5470' 4350' 3100' 3100' 5470' 5520' 5520' 5520' 3100' 3100' 3100' 3100' 5470'

---

1 12 100 24 32 99 98 22 43 253 .13 .67 4 34 44
1 12 200 23 32 99 97 3 36 253 .05 .72 4 34 44
1 12 300 23 31 99 98 0 0 254 .04 .76 4 33 44
1 12 400 23 31 99 97 0 0 253 .09 .85 5 33 44
1 12 500 22 31 99 97 0 0 254 .11 .96 6 35 44
1 12 600 22 30 99 97 0 0 252 .09 1.05 1 -- 44 **
1 12 700 22 31 99 98 0 0 253 .1 1.15 2 37 44 **
1 12 800 23 31 99 97 0 18 252 .12 1.27 4 40 44 **
1 12 900 23 31 99 98 0 0 247 .07 1.34 6 -- 44 **
1 12 1000 26 32 99 99 0 0 245 .14 1.48 6 40 44
1 12 1100 27 33 98 100 0 0 248 .1 1.58 7 43 44
1 12 1200 28 33 99 100 0 0 252 .11 1.69 7 44 4
1 12 1300 29 33 99 100 0 0 247 .14 1.83 7 44 5
1 12 1400 29 33 99 99 0 0 273 .24 2.07 7 44 44


Northwest Avalanche Center
Washington Department of Transportation
Snoqualmie Pass, Washington

3770' temp above Lake Keechelus snow shed

MM/DD Hour Temp Temp Temp RH Wind Wind Wind Hour Total 24 Hr Total Press
PST F F F % Avg Max Dir Prec Prec Snow Snow mb
3760' 3770' 3010' 3010' 3760' 3760' 3760' 3010' 3010' 3010' 3010' 3010'

---

1 12 100 29 29 32 94 34 53 237 .11 1.13 4 25 1009
1 12 200 28 29 32 91 37 55 293 .03 1.16 4 28 1011
1 12 300 28 28 31 91 34 49 227 .02 1.18 4 27 1011
1 12 400 28 28 31 97 25 41 224 .15 1.33 5 27 1012
1 12 500 28 28 30 98 24 36 272 .14 1.47 6 28 1013
1 12 600 27 27 30 97 22 38 292 .09 1.56 0 29 1014
1 12 700 27 28 30 98 12 27 245 .11 1.67 1 29 1015 **
1 12 800 28 28 30 98 8 14 254 .14 1.81 1 34 1016 **
1 12 900 28 29 30 97 5 11 256 .12 1.93 5 35 1016 **
1 12 1000 30 30 32 97 4 16 278 .09 2.02 5 33 1016
1 12 1100 32 31 32 97 12 23 250 .07 2.09 5 36 1017
1 12 1200 32 32 32 97 15 28 242 .16 2.25 6 36 1016
1 12 1300 32 33 32 97 21 46 280 .17 2.42 5 36 1016
1 12 1400 33 33 32 97 16 34 268 .27 2.69 5 37 1017


Northwest Avalanche Center Northwest Avalanche Center
Crystal Mountain Ski Area, Washington Green Valley, Crystal Mountain

Strong winds may affect snowdepth

MM/DD Hour Temp Temp RH RH Wind Wind Wind Wind Hour Total 24 Hr Total MM/DD Hour Temp 24 Hr Total
PST F F % % Min Avg Max Dir Prec Prec Snow Snow PST F Snow Snow
6830' 4570' 6830' 4570' 6830' 6830' 6830' 6830' 4570' 4570' 4570' 4570' 6230' 6230' 6230'

---

---

1 12 100 21 28 97 99 13 28 54 24 .02 .5 9 23 1 12 100 17 12 68
1 12 200 15 26 97 99 11 29 59 214 .02 .52 9 23 1 12 200 15 13 69
1 12 300 18 26 97 99 15 32 63 172 .02 .54 9 23 1 12 300 16 13 69
1 12 400 17 26 97 99 11 30 62 286 .06 .6 9 24 1 12 400 15 14 69
1 12 500 18 26 97 99 10 27 54 281 .08 .68 11 25 ** 1 12 500 16 15 71 **
1 12 600 18 27 97 99 10 25 44 218 .11 .79 0 25 ** 1 12 600 16 17 73 **
1 12 700 19 27 98 99 9 22 44 222 .12 .91 4 33 ** 1 12 700 17 23 79 **
1 12 800 20 27 98 99 7 17 33 258 .06 .97 8 30 ** 1 12 800 18 25 81 **
1 12 900 22 27 98 99 8 19 42 109 .03 1 7 34 1 12 900 20 25 81
1 12 1000 24 28 99 100 9 20 37 160 .03 1.03 8 34 1 12 1000 23 25 81
1 12 1100 26 30 100 100 11 29 56 265 .02 1.05 8 33 1 12 1100 24 0 80
1 12 1200 27 33 100 100 13 35 56 283 .03 1.08 8 32 1 12 1200 25 0 80
1 12 1300 27 33 100 100 14 33 53 281 .05 1.13 8 32 1 12 1300 25 1 80
1 12 1400 29 33 100 100 14 28 46 324 .07 1.2 8 34 1 12 1400 25 2 --

8" new in 2 hours at both locations, 12" in 4 hours in GV!

Northwest Avalanche Center
Paradise, Mt Rainier National Park, Washington

Wind speed not reliable and may record periodically, scheduled for repair

MM/DD Hour Temp RH Wind Wind Wind Hour Total 24 Hr Total Solar
PST F % Avg Max Dir Prec Prec Snow Snow W/m2
5400' 5400' 5380' 5380' 5380' 5400' 5400' 5400' 5400' 5400'

---

1 12 100 23 97 0 0 263 .03 .65 17 91 0
1 12 200 22 96 0 0 259 .04 .69 16 91 0
1 12 300 22 97 0 0 266 .03 .72 16 88 0
1 12 400 23 97 0 0 258 .13 .85 18 93 0 **
1 12 500 23 97 0 0 257 .13 .98 21 -- 0 **
1 12 600 23 97 0 0 268 .07 1.05 22 -- 0 **
1 12 700 24 97 0 0 263 .09 1.14 25 -- 0 **
1 12 800 25 97 0 0 269 .1 1.24 26 99 0 ** 10" new in 5 hours!
1 12 900 25 98 0 0 275 .12 1.36 27 -- 4
1 12 1000 27 98 0 0 271 .11 1.47 28 100 14 <<< third telemetry site in Cascades
1 12 1100 28 98 0 0 271 .12 1.59 29 102 26 to reach 100" snowdepth
1 12 1200 28 98 0 0 266 .19 1.78 29 101 31
1 12 1300 28 99 0 0 267 .16 1.94 30 101 28
1 12 1400 29 99 0 0 266 .2 2.14 31 103 29


Northwest Avalanche Center
White Pass Ski Area, Washington

Wind data not available until new IP address approved by NWS/NOAA

MM/DD Hour Temp Temp RH RH Wind Wind Wind Wind Hour Total Total
PST F F % % Min Avg Max Dir Prec Prec Snow
5800' 4470' 5800' 4470' 5970' 5970' 5970' 5970' 5800' 5800' 5800'

---

1 12 100 21 27 97 87 .03 1.11 80
1 12 200 21 26 96 89 .01 1.12 80
1 12 300 21 26 97 94 .05 1.17 51
1 12 400 21 26 97 92 .06 1.23 81
1 12 500 21 26 97 94 .08 1.31 -- **
1 12 600 22 26 97 95 .15 1.46 -- **
1 12 700 22 27 97 95 .12 1.58 86 **
1 12 800 23 27 98 95 .05 1.63 87 **
1 12 900 24 28 98 94 .05 1.68 --
1 12 1000 24 29 99 93 .06 1.74 --
1 12 1100 26 30 99 94 .05 1.79 88
1 12 1200 28 31 100 95 .06 1.85 89
1 12 1300 28 32 100 96 .07 1.92 88
1 12 1400 29 32 100 97 .08 2 90


Northwest Avalanche Center
Timberline Lodge, Oregon

Prec gage may record snow falling from nearby trees

MM/DD Hour Temp RH Wind Wind Wind Wind Hour Total 24 Hr Total
PST F % Min Avg Max Dir Prec Prec Snow Snow
5880' 5880' 6000' 6000' 6000' 6000' 5880' 5880' 5880' 5880'

---

1 12 100 24 100 7 15 26 273 .19 1.56 13 60
1 12 200 21 100 8 15 27 271 .17 1.73 13 61
1 12 300 22 100 8 15 32 287 .07 1.8 14 62
1 12 400 22 100 8 14 24 278 .11 1.91 14 62
1 12 500 22 100 7 13 24 279 .07 1.98 15 62
1 12 600 23 100 6 13 26 282 .12 2.1 2 63 **
1 12 700 24 100 8 13 24 289 .12 2.22 2 64 **
1 12 800 24 100 7 14 25 291 .09 2.31 3 64 **
1 12 900 26 100 8 14 24 283 .17 2.48 4 65 **
1 12 1000 28 100 8 13 24 276 .21 2.69 5 --
1 12 1100 29 100 6 12 21 273 .19 2.88 5 --
1 12 1200 31 100 7 13 21 283 .17 3.05 6 --
1 12 1300 31 100 7 14 22 282 .13 3.18 6 67
1 12 1400 31 100 7 14 22 281 .17 3.35 6 67


Northwest Avalanche Center
Mt Hood Meadows Ski Area, Oregon

MM/DD Hour Temp Temp RH RH Wind Wind Wind Hour Total 24 Hr Total Press
PST F F % % Avg Max Dir Prec Prec Snow Snow mb
6540' 5380' 6540' 5380' 6540' 6540' 6540' 5380' 5380' 5380' 5380' 5380'

---

1 12 100 20 26 90 97 13 29 281 .19 1.56 14 47 1010
1 12 200 18 24 90 96 15 43 196 .16 1.72 15 49 1011
1 12 300 18 24 90 96 18 32 264 .06 1.78 15 49 1012
1 12 400 18 24 90 96 15 33 258 .11 1.89 15 50 1013
1 12 500 19 24 90 96 15 30 266 .08 1.97 16 51 1014
1 12 600 20 25 90 97 15 31 239 .1 2.07 1 51 1014 **
1 12 700 21 26 91 97 18 31 237 .09 2.16 2 51 1014 **
1 12 800 21 26 91 97 19 39 237 .09 2.25 4 51 1015 **
1 12 900 24 28&nb

I can confirm it snowed intensely Sunday morning. Source - after quick dawn patrol my hat bill had a few inches on it .... Even before the face plant.

Update #7: 168 hours (1 week) after initial post, models predictions have verified with snowfall totals up to 4-8 ft at higher elevations, with 1-3 ft even at lower elevations!

Another day later, and 2 more subsequent runs of the UW WRF-GFS model at 12-hour intervals continue to show the storm cycle gradually tapering off on Monday, with precip and snowfall ending from south to north by Tuesday. This storm cycle has proceeded largely as predicted several days prior to its start by the models, and it really is a stunning success that weather models could quite accurately predict this event from 5-7 days out, including reasonably correct snowfall amounts. Forecasting precip amounts accurately is quite difficult (much more so than temperature or wind), and doing so for snowfall amounts is even more difficult.

The final tail end of this storm cycle is now underway on Monday, with snow levels rising above 4000-5000 ft on Sunday afternoon and into Monday. Snow levels appear to have risen a bit more than the model predicted, but only by about 500-1000 ft higher. Additional snowfall during the 24 hour period through 4am Tuesday is predicted to be 6-12" over the northern Washington Cascades above 4000-5000 ft, with barely a few inches more for the Olympics and southern Washington and Mount Hood, and almost nothing farther south in Oregon:



This loop shows how the model predictions for snowfall during the final day of the storm cycle through 4am Tuesday have evolved between 6 subsequent runs over the last 3 days, the D(model)/D(t):
www.atmos.washington.edu/~ovens/wxloop.c...4+v2014011412///+-st


Storm cycle summary and totals:

About 1-6 ft of new snow has fallen at most mountain measurement sites in southwest BC, Washington, and Oregon during the 7 days since the storm cycle began early Tuesday, January 7, with the greatest amounts at favored locations on the Cascade Crest and volcanoes, and lesser amounts east of the Crest, in the Olympics, and in southern Oregon. Low elevations did not fare well during this storm cycle, with snow levels only briefly dropping below 2000 ft in southwest BC and Washington, and 3000 ft in northern Oregon -- snowfall amounts of 1 ft or greater were generally received only above 2000 ft in the north ranging to 4000 ft in Oregon. Total precipitation exceeded 10" at the wettest sites on Mounts Baker, Saint Helens and Hood, plus Snoqualmie Pass and the Tolt River headwaters west of Stevens Pass. Given precip totals of 10-12" or even 15" (see table below), snowfall totals of over 8 ft (possibly 10 ft) were likely received above 6000 ft on Mount Baker and 7000 ft on Mounts Saint Helens and Hood where the precip remained entirely snow, versus several periods of mixed precip and extremely dense wet snowfall recorded at Baker Ski Area, Meadows, and Timberline.

Snowdepths have increased substantially at most measurement sites in the Cascades and Olympics, doubling or even tripling at many sites especially at lower elevations and in Oregon. Snowdepths have generally increased by about 2-4 ft at most sites above 3000 ft during this storm cycle, topped by the 50" increase seen at Mount Rainier Paradise. Snowdepth at 3 sites in the Cascades has topped the 100" mark: first the Chilliwack River BCRFC site on Saturday afternoon (5300 ft in the BC Cascades just north of the US border near Mount Baker), followed a few hours later by the Brown Top SNOTEL site (5800 ft near Mount Redoubt in the North Cascades), and then Paradise on Sunday morning. Snowdepth at Paradise is now roughly 100% of normal for this date! -- it's shocking to see that, given how far below normal this season has been thus far (of course, obviously the new snowfall will rapidly settle and reduce the depth below 100% of normal in a few days -- but January snowdepth values often include much new unconsolidated snow like this). The Chilliwack River BCRFC site is now slightly above 100% of normal for snowdepth and snow water equivalent:



The Blackwall Peak BCRFC site in the BC Cascades (Manning Park) is roughly 100% of normal too, and the Brown Top SNOTEL might be at or above normal too, except it was only installed in 2009 and so normal values are not yet established. All other sites in the Cascades, Olympics, and southwest BC remain below normal snowdepth, but a few others are close to normal especially farther north: Whistler Mountain, Baker Ski Area, and Stevens Pass are all roughly 90% of normal as of now.

One big Pacific Northwest storm cycle can really fix a low snowpack! And this was merely a big storm cycle, not a huge one at all -- huge Northwest storm cycles can deliver 10-15 ft of snow during 1 week, and sometimes with much lower snow levels (at times) than this one. This storm cycle will be remembered for "saving the season" at several ski areas in Washington and southwest BC, as they finally acquired enough base depth to open for the first time this season (Snoqualmie Summit and Alpental in WA; Mt Washington, Mt Seymour, and Hemlock Valley in BC). However, several other Pacific Northwest ski areas remain closed or in rope-tow-only operation as the storm did not bring them enough snow to open, especially so in Oregon (Mt Cain in BC, Loup Loup in WA; Mt Hood Ski Bowl, Cooper Spur, Hoodoo, Willamette Pass, and Mt Ashland in OR; Mt Shasta Ski Park in CA, which had partially opened for a few days after Christmas, then closed). The snowpack remains far below normal in those areas, still 50% of normal or less. Stunningly, the snowdepth is still 0-10% of normal even at high-elevation sites in northern California on Mount Shasta and Lassen Peak which normally build an extremely deep snowpack.


Table of total snowfall and precip (some amounts may be approximate) for the 7 day period from January 7 through Tuesday morning, January 14, along with the increase in snowdepth from January 7 up to the maximum depth reached during this storm cycle (most maxima occurred on January 12, some on the 11th or 13th):

Increase in
Total Snowdepth Total
Measurement Site Elevation Snowfall Jan7 >>> Max Precip Notes

---

==== British Columbia ====
Burnt Bridge Creek BCRFC 4360 ft 3.5 ft 43" >>> 76" 4.5" (way north, E of Bella Coola)
Tenquille Lake BCRFC 5480 ft 3 ft 43" >>> 71" 3.5" (N of Whistler, all snow)
Whistler Mountain 5400 ft 3 ft 42" >>> 69" --
Whistler Village 2200 ft 1.5 ft 1" >>> 13" --
Callaghan Valley 2900 ft 2.5 ft 9" >>> 35" 3" (W of Whistler)
Squamish River BCRFC 4550 ft 5 ft 48" >>> 83" 6.5" (almost all snow)
Spuzzum Creek BCRFC 3930 ft 4 ft 33" >>> 66" 8" (near Harrison Lake)
Chilliwack River BCRFC 5320 ft 5 ft 72" >>> 109" 7"?? (BC Cascades, almost all snow)
Blackwall Peak BCRFC 6350 ft 3 ft 45" >>> 71" 3.5" (BC Cascades, all snow)
Jump Creek BCRFC 3720 ft 4 ft 8" >>> 46" 8" (Vancouver Island)

======= Washington =======
Hurricane Ridge 5250 ft 2 ft 14" >>> 30" 3.5"
Waterhole SNOTEL 5010 ft 2 ft 14" >>> 32" 5" (N side of Olympics)
Buckinghorse SNOTEL 4870 ft 3 ft 8" >>> 36" 9" (central Olympics)
Mount Crag SNOTEL 3960 ft 2 ft 2" >>> 19" 4" (E side of Olympics)
Mt Baker Ski Area 4200 ft 5 ft 59" >>> 94" 8" (snowdepth flaky +/- 5")
Mt Baker, MF Nooksack 4970 ft 4 ft 51" >>> 79" 10" (NW side of Mt Baker)
Mt Baker, Marten Ridge 3520 ft 4 ft 36" >>> 67" 12.5" (E side of Mt Baker)
Mt Baker, Elbow Lake 3040 ft 3 ft 16" >>> 38" 15" !! (SW side of Mt Baker)
Brown Top SNOTEL 5830 ft 5 ft 64" >>> 105" 6.5" (almost all snow)
Beaver Pass SNOTEL 3630 ft 3 ft 24" >>> 51" 5.5"
Swamp Creek SNOTEL 3930 ft 3 ft 23" >>> 45" 4.5" (on Hwy 20, W of Rainy Pass)
Washington Pass 5450 ft 3.5 ft 32" >>> 68" 4" (almost all snow)
Harts Pass SNOTEL 6500 ft 4 ft 44" >>> 76" 5" (all snow)
Mazama 2200 ft 0.7 ft 8" >>> 15" 1"
Park Creek Ridge SNOTEL 4600 ft 3.5 ft 26" >>> 56" 6" (SE ridge of Mt Buckner)
Holden Village 3220 ft 2.5 ft 6" >>> 25" 4.5"
Lyman Lake SNOTEL 5980 ft 4 ft 56" >>> 89" 5"
Trinity SNOTEL 2930 ft 3 ft 12" >>> 42" 6"
Alpine Meadows SNOTEL 3500 ft 3 ft 26" >>> 44" 13" (Tolt River headwaters)
Skookum Creek SNOTEL 3310 ft 2 ft 16" >>> 31" 12" (Tolt River headwaters)
Stevens Pass, Grace Lakes 4800 ft 5 ft 57" >>> 94" --
Stevens Pass 3950 ft 4 ft 36" >>> 67" 7"
Sasse Ridge SNOTEL 4340 ft 3 ft 24" >>> 50" 4.5" (E of Salmon La Sac Rd)
Blewett Pass SNOTEL 4240 ft 1.5 ft 6" >>> 21" 2.5" (near old Blewett Pass)
Grouse Camp SNOTEL 5390 ft 1.5 ft 16" >>> 31" 2.5" (between Blewett & Mission)
Mission Ridge 5160 ft 1 ft 12" >>> 23" 1.5"
Top of Alpental 5470 ft 5 ft 80" >>> 94" -- (snowdepth may be suspect?)
Alpental Base 3100 ft 2.5 ft 23" >>> 44" 9.5"
Snoqualmie Pass 3000 ft 2.5 ft 15" >>> 37" 10"
Stampede Pass 3850 ft 2.5 ft 12" >>> 35" 6.5"
Corral Pass SNOTEL 5800 ft 3.5 ft 31" >>> 60" 5" (N of Crystal Mtn)
Crystal Mtn, Green Valley 6230 ft 3.5 ft 46" >>> 81" --
Crystal Mtn Base 4570 ft 2.5 ft 11" >>> 34" 3"
Morse Lake SNOTEL 5400 ft 4 ft 27" >>> 60" 5" (just S of Crystal Mtn)
Cayuse Pass SNOTEL 5240 ft 4 ft 25" >>> 59" 6"
Mt Rainier, Sunrise 6400 ft 2 ft 28" >>> 48" --
Mt Rainier, Paradise 5400 ft 5.5 ft 56" >>> 106" 7"
Mt Rainier, Paradise SNOTEL 5130 ft 5 ft 39" >>> 89" 8"
Mt Rainier, Longmire 2700 ft 1 ft 0" >>> 13" 4"
Bumping Ridge SNOTEL 4610 ft 3.5 ft 11" >>> 42" 4.5" (SE of Chinook Pass)
White Pass Ski Area (top) 5800 ft 4.5 ft 49" >>> 91" 6"
White Pass E.S. SNOTEL 4440 ft 2.5 ft 7" >>> 30" 4.5"
Mt Adams, Potato Hill 4510 ft 3 ft 19" >>> 45" 5" (N side of Mt Adams)
Surprise Lakes SNOTEL 4290 ft 3 ft 21" >>> 46" 9" (Indian Heaven, SW of Adams)
Mt St Helens, Swift Creek 4440 ft 3 ft 11" >>> 37" 10" (S side of St Helens)
Mt St Helens, Sheep Canyon 3990 ft 3 ft 9" >>> 32" 9.5" (W side of St Helens)
Mt St Helens, June Lake 3440 ft 3 ft 6" >>> 32" 12" (SE side of St Helens)
Mt St Helens, Marble Mtn 2700 ft 1 ft 0" >>> 12" -- (very approximate number)

========= Oregon =========
Blazed Alder SNOTEL 3650 ft 2 ft 4" >>> 22" 9" (NW of Mt Hood)
Mt Hood, Red Hill SNOTEL 4410 ft 3 ft 10" >>> 33" 8" (N side of Mt Hood)
Mt Hood, Timberline 5880 ft 5 ft 29" >>> 68" 11.5"
Mt Hood, Test Site SNOTEL 5370 ft 4.5 ft 25" >>> 56" 8" (just S of Timberline)
Mt Hood, Meadows 5380 ft 4.5 ft 25" >>> 54" 9.5"
Mt Hood, Mud Ridge SNOTEL 4070 ft 2 ft 8" >>> 26" 5" (S of Mt Hood)
Mt Hood, Government Camp 3980 ft 1.5 ft 0" >>> 14" 6" (S side of Mt Hood)
Santiam Pass (Hogg Pass) 4790 ft 1.5 ft 4" >>> 18" 2.5"
Hoodoo Ski Area 5010 ft 2 ft 8" >>> 25" --
Bear Grass SNOTEL 4720 ft 2.5 ft 8" >>> 30" 8" (W of Mt Washington)
McKenzie Pass SNOTEL 4770 ft 2.5 ft 16" >>> 36" 7" (near Obsidian Trailhead)
Three Creeks Meadow SNOTEL 5690 ft 2 ft 3" >>> 20" 2.5" (E of Three Sisters)
Mt Bachelor, West Village 6300 ft 3.5 ft 26" >>> 64" --
Irish Taylor SNOTEL 5540 ft 2.5 ft 18" >>> 41" 4.5" (SW of Mt Bachelor)
Willamette Pass, Cascade Smt 5100 ft 2.5 ft 12" >>> 33" 4"
Diamond Peak, Summit Lake 5610 ft 2 ft 14" >>> 30" 3" (S side of Diamond Peak)
Diamond Lake SNOTEL 5280 ft 0.5 ft 1" >>> 7" 2" (extremely rain-shadowed site)
Crater Lake, Rim 7050 ft 2.5 ft 21" >>> 42" -- (south rim of caldera)
Crater Lake, Park HQ 6470 ft 2.5 ft 4" >>> 32" --
Crater Lake, Lagoon 6370 ft 2.5 ft 14" >>> 38" 3" (near Park HQ)
Crater Lake, Annie Springs 6000 ft 2 ft 8" >>> 26" 3" (near Park entrance)
Pelican Butte, Cold Springs 5940 ft 1.5 ft 6" >>> 19" 3" (NW side of Pelican Butte)
Mt McLoughlin, Fourmile Lake 5970 ft 1.5 ft 6" >>> 17" 2.5" (E side of Mt McLoughlin)
Mt McLoughlin, Billie Creek 5280 ft 1.5 ft 5" >>> 18" 3.5" (SE side of Mt McLoughlin)
Big Red Mountain SNOTEL 6050 ft 0.5 ft 2" >>> 7" 1" (Siskiyou Mtns, SW of Ashland)

======= California =======
Medicine Lake 6700 ft 0.2 ft 0" >>> 2" 0.5" (Medicine Lake Volcano caldera)
Mt Shasta, Old Ski Bowl 7600 ft 0.2 ft 6" >>> 8" -- (south side of Mt Shasta)
Mt Shasta, Sand Flat 6750 ft 0.1 ft 4" >>> 5" -- (SW side of Mt Shasta)
Mt Eddy 6510 ft 0.4 ft 1" >>> 6" -- (west of Mt Shasta across I-5)
Lassen Peak, Lake Helen 8250 ft data outage, snowdepth < 1 ft (SW side of Lassen Peak)
Lassen, Harkness Flat 6200 ft 0.2 ft 0" >>> 2" -- (well east of Lassen Peak)


Throughout California, there was only about 2-5" of new snow (all of which fell on Saturday) for anywhere in the California Cascades and the Sierra Nevada.


The persistent ridge of high pressure off the West Coast is already rebuilding northward, bringing this storm cycle to an end and bringing back the mostly sunny warm weather for Tuesday-Friday, especially south (northern WA and southwest BC may remain partly cloudy and have higher winds). It's time to head out and enjoy the new twice-as-deep snowpack, especially above-treeline on the volcanoes.

Details beyond that point still remain murky and very uncertain as of now, with subsequent runs of the extended GFS model shifting around predictions during the 7-16 day time frame. Currently it looks like a weak system may brush northern WA while heading primarily for the central BC coast on Saturday, followed by the ridge rebuilding strongly on Sunday-Monday.


[size=small](Edited in February to add Callaghan Valley numbers to table.)[/size]

I love the Amar Weather Tracker.

Me too, thanks Amar. Let's do this every weekend!!

ditto.... very educational posts Amar. thanks for all the info.