- Posts: 413
- Thank you received: 0
January 4, 2013 Alpental
- Griff
- [Griff]
- Topic Author
- Offline
- Senior Member
Skiing wasn't that bad actually, but I really dont dig the whole ice over thing and no vis with the goggles iced up.
So I didnt see it coming at all and am wondering if anyone did?? I live just down the road in Snoqualmie and pay a lot of attention the telemetry and so on.
Would enjoy hearing some thoughts on predicting freezing rain.........
Please Log in or Create an account to join the conversation.
- Robie
- [Robie]
- Offline
- Premium Member
- Posts: 554
- Thank you received: 0
Thinking about predicting it. It was cold enough at the road to snow but there was warmer moist air above and never got a chance to turn to snow. So in a nutshell be wary of inversions. . I thought for sure we would hit some snow but never did. I'm sure when people took thier jackets off they would be frozen stiff and stand alone.
Please Log in or Create an account to join the conversation.
- Amar Andalkar
- [andalkar]
- Offline
- Premium Member
- Posts: 635
- Thank you received: 0
One word - freezing rain. Okay that is two actually. LOL. Probably should be 3 words like f*&ckin freezing rain.
Skiing wasn't that bad actually, but I really dont dig the whole ice over thing and no vis with the goggles iced up.
So I didnt see it coming at all and am wondering if anyone did?? I live just down the road in Snoqualmie and pay a lot of attention the telemetry and so on.
Would enjoy hearing some thoughts on predicting freezing rain.........
Sure, I'll try! This is pretty much a standard weather pattern that causes a high likelihood of freezing rain at Snoqualmie Pass (and sometime Stevens, White, and other passes too). I wasn't certain that freezing rain would occur, but it seemed very likely given the following set of circumstances.
Most importantly, there was pre-existing cold easterly flow through the passes, with warmer temperatures above pass level -- this had been going on for several days, and was plainly obvious in the NWAC telemetry from Washington, Stevens, Snoqualmie, Chinook, and White Passes. These stations all had temps of 8-20 °F at pass levels, but about 10-20 degrees warmer at upper sites around 5500-6500 ft, i.e. 1000-2500 ft above pass level.
Couple that with an incoming warmer weather system, whose leading warm front brings precipitation and additional relatively-warm air aloft to override the cold easterly flow. The precipitation starts off as snowflakes (almost all precip at this latitude starts off as snowflakes, year-round), which melt as they fall through the warm above-freezing layer, then refreeze as they fall through the colder air below (making sleet) or if the layer of cold air is thin, they refreeze upon hitting the cold surface (making freezing rain).
From Thursday's NWAC Mountain Weather Forecast (archived at www.nwac.us/archive/sabnw_2013-01-03-1405.html), here are the predicted snow levels (and remember that freezing levels are about 500-1000 ft higher than snow levels):
SNOW LEVELS
Olympics, Cascades--Mt Baker (N) to Snoq Pass (C) to Mt Hood (S)
Time Olympics North Central South
Thursday afternoon 5000 5500 5500 6000
Thursday night and Friday morning 4000 2500 4000 4500
Friday afternoon 4000 3500 4500 6000
Friday night 5000 5000 5500 6500
Except at the surface Cascade passes and east slopes through Friday.
... Note that surface snow levels are common near the passes during easterly pass flow and may result in multiple snow / freezing levels.
So this looks like pretty much a classic recipe for near-certain freezing rain. I'm not sure why the NWAC Mountain Weather Forecast did not mention it. Even this morning's forecast (www.nwac.us/archive/sabnw_2013-01-04-0727.html) mentioned "local freezing rain" only for the Mt Hood area (which is affected by similar cold easterly flow through the Columbia Gorge), but not for Snoqualmie.
And a look at just the Snoqualmie telemetry might fool one into thinking all is well:
Northwest Weather and 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 3 1800 16 15 18 90 20 28 123 0 0 0 60 1022
1 3 1900 15 15 18 91 21 34 128 0 0 0 60 1023
1 3 2000 15 15 18 93 19 26 156 .04 .04 -1 59 1022
1 3 2100 15 15 18 93 20 28 121 .04 .08 1 61 1022
1 3 2200 16 15 18 94 20 28 165 .06 .14 2 62 1022
1 3 2300 15 15 18 94 21 27 168 .06 .2 2 62 1023
1 4 0 15 15 18 93 18 26 130 .07 .27 3 63 1023
1 4 100 14 15 18 94 17 26 136 .06 .33 3 63 1023
1 4 200 13 15 18 93 18 28 154 .05 .38 4 63 1024
1 4 300 15 16 18 94 19 27 139 .04 .42 4 63 1024
1 4 400 15 16 18 94 24 28 125 .03 .45 4 63 1024
1 4 500 15 16 18 94 22 28 124 .04 .49 4 63 1024
1 4 600 16 17 19 94 15 20 120 .02 .51 0 63 1024
1 4 700 15 17 19 94 14 18 123 .03 .54 0 63 1024
1 4 800 18 17 19 94 14 17 130 .02 .56 0 63 1024
1 4 900 18 19 20 94 15 19 126 .03 .59 0 63 1025
1 4 1000 18 21 21 93 15 20 132 .02 .61 0 63 1025
1 4 1100 20 23 24 89 14 17 134 .05 .66 1 63 1025
1 4 1200 23 25 26 87 12 17 127 .1 .76 1 63 1025
1 4 1300 22 25 25 88 14 16 128 0 .76 1 63 1025
1 4 1400 24 28 26 89 13 17 137 0 .76 1 63 1024
1 4 1500 27 27 25 91 12 16 131 0 .76 1 63 1024
1 4 1600 21 22 23 96 21 25 116 0 .76 1 63 1024
1 4 1700 20 21 23 97 20 24 112 0 .76 1 63 102
Including Alpental shows very worrisome temperatures aloft, but still marginally below freezing:
Northwest Weather and Avalanche Center
Alpental Ski Area, Washington
Wind gages unheated and may rime
4350 ft station phone line out--under repair
24 hr snow 5470' may be wind affected
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 3 1800 22 19 92 69 12 18 129 0 0 0 73 -0
1 3 1900 17 19 93 86 18 26 109 0 0 0 74 -1
1 3 2000 19 19 94 95 21 28 118 .02 .02 1 74 -0
1 3 2100 18 19 95 95 25 32 129 .08 .1 1 73 1
1 3 2200 20 18 95 95 26 31 150 .1 .2 2 75 1
1 3 2300 22 18 95 96 23 29 170 .07 .27 2 74 1
1 4 0 22 19 95 98 25 42 193 .08 .35 3 75 1
1 4 100 24 19 94 97 27 38 217 .06 .41 3 76 1
1 4 200 25 19 94 98 24 38 223 .06 .47 3 75 2
1 4 300 27 19 94 99 25 38 235 .03 .5 3 76 2
1 4 400 29 19 94 100 25 42 236 .02 .52 3 74 2
1 4 500 29 19 94 100 23 48 236 .01 .53 3 76 2
1 4 600 29 20 94 99 23 36 237 .01 .54 3 77 2
1 4 700 29 20 94 100 22 38 237 .02 .56 3 75 2
1 4 800 29 20 94 99 21 35 236 .03 .59 0 78 2
1 4 900 29 21 94 99 19 29 236 .02 .61 0 75 -0
1 4 1000 30 23 93 99 16 30 238 0 .61 1 76 -0
1 4 1100 30 25 90 99 13 21 239 .01 .62 1 75 -0
1 4 1200 31 26 90 99 10 20 237 .01 .63 1 76 -0
1 4 1300 32 26 90 99 0 0 230 0 .63 1 75 -1
1 4 1400 32 27 89 100 0 0 218 0 .63 1 75 -1
1 4 1500 31 25 92 98 0 0 164 0 .63 1 75 -0
1 4 1600 29 24 95 97 0 0 96 0 .63 1 75 -0
1 4 1700 28 24 96 97 0 0 126 0 .63 1 76 -1
However, the 4350 ft temperature is missing, and this is critical: that temperature was almost certainly above freezing all day, which would have revealed the freezing rain. How does one verify that? The Olallie Meadows SNOTEL site, located 4 miles SSW of Snoqualmie Pass on the west ridge of Mt Catherine at 4030 ft, provides the answer:
OLALLIE MEADOWS SNOTEL Data Report - All Readings
Basin: Snoqualmie (HUC 17110010) Elevation: 4030.00
Snow YTD Current Previous Day's Temp
Time SWE Depth Precip Temp (°F)
Date (PST) (in) (in) (in) (°F) Max Min Avg
2013-01-03 1800 26.7 77.0 56.6 18.0 21.4 16.2 18.1
2013-01-03 1900 26.7 77.0 56.5 18.0 21.4 16.2 18.1
2013-01-03 2000 26.7 77.0 56.4 18.0 21.4 16.2 18.1
2013-01-03 2100 26.8 78.0 56.5 18.1 21.4 16.2 18.1
2013-01-03 2200 26.9 79.0 56.6 18.1 21.4 16.2 18.1
2013-01-03 2300 26.9 79.0 56.5 18.5 21.4 16.2 18.1
2013-01-04 0000 27.0 79.0 56.6 18.1 20.7 15.4 17.8
2013-01-04 0100 27.1 79.0 56.5 19.0 20.7 15.4 17.8
2013-01-04 0200 27.1 80.0 56.5 18.0 20.7 15.4 17.8
2013-01-04 0300 27.2 80.0 56.5 18.5 20.7 15.4 17.8
2013-01-04 0400 27.2 80.0 56.5 18.5 20.7 15.4 17.8
2013-01-04 0500 27.2 80.0 56.5 19.4 20.7 15.4 17.8
2013-01-04 0600 27.2 80.0 56.3 31.6 20.7 15.4 17.8
2013-01-04 0700 27.3 78.0 56.3 33.3 20.7 15.4 17.8
2013-01-04 0800 27.4 79.0 56.3 33.6 20.7 15.4 17.8
2013-01-04 0900 27.4 79.0 56.5 34.2 20.7 15.4 17.8
2013-01-04 1000 27.4 79.0 56.7 34.3 20.7 15.4 17.8
2013-01-04 1100 27.4 79.0 56.9 35.1 20.7 15.4 17.8
2013-01-04 1200 27.4 79.0 56.9 35.1 20.7 15.4 17.8
2013-01-04 1300 27.4 79.0 57.0 32.0 20.7 15.4 17.8
2013-01-04 1400 27.4 79.0 57.3 30.6 20.7 15.4 17.8
2013-01-04 1500 27.4 79.0 57.5 31.1 20.7 15.4 17.8
2013-01-04 1600 27.4 78.0 57.5 26.6 20.7 15.4 17.8
2013-01-04 1700 27.4 79.0 57.4 25.5 20.7 15.4 17.8
So temps had gone above freezing at 4000 ft by 7am, while precipitation was still coming down. Freezing rain for sure.
It's best to look at all the regional telemetry sites to get the full picture! Looking at data from the several NWAC sites near Stevens Pass also shows the above-freezing air around 4800-5200 ft. The most dramatic thing in the Stevens telemetry is the sudden wind reversal from easterly ENE to SW around 3-4am at both the Brooks and Tye Mill sites, accompanied by a rapid 15-20 degree temperature rise, presumably as the warm front arrived at that elevation and location. Cold easterly air continued to flow at pass level for most of the day, which shows that there may have been some freezing rain there too, although the precip was diminishing by the time temps warmed aloft, so perhaps they were spared:
Northwest Weather and 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
PST F F % % Avg Max Dir Prec Prec Snow Snow
4850' 3950' 4850' 3950' 4850' 4850' 4850' 3950' 3950' 3950' 3950'
1 3 1800 11 15 90 90 14 24 59 0 0 1 71
1 3 1900 11 15 90 90 15 27 52 0 0 1 71
1 3 2000 11 15 91 91 14 27 47 0 0 1 71
1 3 2100 11 15 90 90 15 26 54 .02 .02 1 72
1 3 2200 11 15 91 90 16 26 56 .02 .04 1 72
1 3 2300 12 15 91 90 15 26 42 .03 .07 2 73
1 4 0 12 15 91 90 14 25 45 .04 .11 3 73
1 4 100 11 15 91 90 12 22 48 .01 .12 3 73
1 4 200 12 15 91 91 9 17 56 .03 .15 3 73
1 4 300 14 15 92 91 4 11 49 .01 .16 3 74
1 4 400 29 15 100 90 5 15 216 .02 .18 3 74
1 4 500 31 15 100 91 7 20 216 0 .18 3 74
1 4 600 31 16 100 91 6 18 220 0 .18 0 74
1 4 700 31 16 100 91 6 14 227 0 .18 0 74
1 4 800 31 17 100 90 6 14 218 .01 .19 0 74
1 4 900 32 17 100 90 5 12 212 .01 .2 0 74
1 4 1000 32 18 100 90 4 10 217 .01 .21 1 74
1 4 1100 32 19 100 89 4 11 214 0 .21 0 73
1 4 1200 32 20 100 89 3 10 201 0 .21 1 73
1 4 1300 33 22 100 89 2 8 224 0 .21 0 73
1 4 1400 32 22 100 89 1 7 225 .01 .22 1 73
1 4 1500 33 23 100 88 0 1 290 0 .22 1 73
1 4 1600 30 20 100 92 2 7 355 0 .22 1 73
1 4 1700 29 19 100 94 3 8 38 0 .22 1 73
Northwest Weather and Avalanche Center
Tye Mill Chair (5180'), Skyline Chair (5250')
Stevens Pass Ski Area, Washington
Wind gages unheated and may rime
New precip gage installed 1 Jan 2013
MM/DD Hour Temp Temp Wind Wind Wind Hour Total Total
PST F F Avg Max Dir Prec Prec Snow
5180' 5250' 5180' 5180' 5180' 5250' 5250' 5250'
1 3 1800 9 11 6 11 61 0 0 74
1 3 1900 9 20 6 10 57 0 0 74
1 3 2000 9 21 7 12 53 0 0 75
1 3 2100 9 16 10 14 51 0 0 74
1 3 2200 9 18 9 13 57 0 0 75
1 3 2300 9 23 10 13 55 0 0 72
1 4 0 10 25 9 11 55 0 0 75
1 4 100 10 27 8 10 52 0 0 75
1 4 200 12 29 6 11 55 0 0 75
1 4 300 26 30 2 15 187 0 0 74
1 4 400 27 30 5 16 207 0 0 77
1 4 500 28 29 1 9 228 0 0 77
1 4 600 29 30 1 8 230 0 0 75
1 4 700 29 30 1 5 219 0 0 76
1 4 800 30 30 1 9 214 0 0 76
1 4 900 31 30 7 19 199 0 0 320
1 4 1000 32 32 2 10 194 0 0 77
1 4 1100 32 32 2 12 177 0 0 76
1 4 1200 31 31 14 26 208 0 0 76
1 4 1300 33 34 8 29 193 0 0 76
1 4 1400 32 32 2 11 185 0 0 76
1 4 1500 33 32 0 4 159 0 0 76
1 4 1600 31 29 0 5 62 0 0 76
1 4 1700 28 29 1 7 21 0 0 77
Northwest Weather and Avalanche Center
Washington Department of Transportation
Grace Lakes, Stevens Pass, Washington
Wind gage power out- scheduled for repair
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 3 1800 11 88 3 8 322 0 0 95 8
1 3 1900 11 89 3 8 322 0 0 94 8
1 3 2000 13 89 3 7 322 0 0 96 8
1 3 2100 12 89 4 9 322 0 0 96 8
1 3 2200 13 89 4 10 322 0 0 97 8
1 3 2300 12 89 5 12 322 0 0 96 8
1 4 0 14 89 4 12 322 0 0 97 9
1 4 100 15 89 3 8 322 0 0 98 9
1 4 200 22 95 1 4 322 0 0 97 9
1 4 300 26 96 0 3 322 0 0 95 9
1 4 400 27 95 1 3 322 0 0 94 9
1 4 500 28 97 0 4 322 0 0 93 9
1 4 600 30 97 0 3 322 0 0 92 9
1 4 700 30 97 0 2 346 0 0 -132 9
1 4 800 31 98 0 4 355 0 0 216 9
1 4 900 32 98 0 2 344 0 0 94 7
1 4 1000 32 97 0 2 11 0 0 96 9
1 4 1100 33 97 0 3 15 0 0 96 9
1 4 1200 33 97 1 3 21 0 0 96 9
1 4 1300 33 97 0 3 23 0 0 97 9
1 4 1400 33 97 0 1 16 0 0 97 9
1 4 1500 32 97 0 0 16 0 0 97 9
1 4 1600 31 97 0 0 13 0 0 97 9
Maybe someone who was at Stevens today can report on whether there was any freezing rain there.
Please Log in or Create an account to join the conversation.
- Amar Andalkar
- [andalkar]
- Offline
- Premium Member
- Posts: 635
- Thank you received: 0
We woke to a few inches of new, light fluffy snow. It was an unexpected treat. Riding up higher in the lifts, snow was needle shaped until it tappered off to a mist--nearly tropical after yesterday. The inversion was palpable. Warm buttery new snow on top, cooler at the base. The mist was enough to coat the goggles up high and froze to limit visibility half way down. Snow underfoot was great until we left at 10:30 to get someone to work on time. We suspect conditions would have morphed significantly as the sun continued to push through, and the inversion continued. Strange indeed. Take care in the side and backcountry this weekend.
It looks like the conditions were right on the edge of freezing rain at Stevens, at least in the morning.
And more info about the freezing rain in Jan. 4 2013 Snoqualmie :
4" of light and fluffy fell last night (and skied fantastic) but it switched over to freezing rain/rain in the early am with a thin 2-3mm crust developing on the top. I skipped the touring and went to Alpental where the inversion could be felt with a warm blast above ~4300ft. Still below freezing but more rain-like up to the top of 2. Poor visibility and icy goggles, but the snow skied ok where it's untracked or smoothed in by the wind, if not a bit like paste. It cleared later above 4300 ft with the inversion fog filling the valley again.
Please Log in or Create an account to join the conversation.
- wolfs
- [wolfs]
- Offline
- Senior Member
- Posts: 262
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- sheispiste
- [sheispiste]
- Offline
- Junior Member
- Posts: 105
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- flowing alpy
- [flowing alpy]
- Offline
- Platinum Member
- Posts: 1272
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Griff
- [Griff]
- Topic Author
- Offline
- Senior Member
- Posts: 413
- Thank you received: 0
Seriously, your discussion regarding multiple sources of info really struck home to me. I always keep an eye on the NWAC telemetry but don't usually go beyond that. Perhaps if I did I could have seen this better.
True that I always keep an eye on things when we have the strong east flow going, but was not really paying much attention to the inversion (even though I had skied it three days earlier on Tuesday the 1st).
Lesson learned, thanks again bro!!
Please Log in or Create an account to join the conversation.
- freg
- [freg]
- Offline
- New Member
- Posts: 28
- Thank you received: 0
Now if I can just figure out whether Alpy night skiing will be good or terrible tonight/ tomorrow night...
Please Log in or Create an account to join the conversation.
- Griff
- [Griff]
- Topic Author
- Offline
- Senior Member
- Posts: 413
- Thank you received: 0
As far anything else I think you can assume some wet conditions........
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 6 1500 24 33 96 96 13 24 238 0 0 0 73 0
1 6 1600 23 32 98 97 14 26 235 .01 .01 0 75 -0
1 6 1700 23 32 98 96 15 26 233 .01 .02 1 71 1
1 6 1800 22 31 98 97 17 31 235 .01 .03 0 71 1
1 6 1900 22 31 98 96 19 39 238 0 .03 1 75 1
1 6 2000 22 30 97 96 11 20 233 .01 .04 1 74 1
1 6 2100 23 31 98 96 12 19 228 .02 .06 1 75 2
1 6 2200 23 30 99 98 16 29 217 .03 .09 2 75 2
1 6 2300 24 30 99 97 19 31 219 .04 .13 2 75 3
1 7 0 25 30 99 98 19 30 222 .06 .19 3 75 3
1 7 100 25 30 99 97 19 39 229 .08 .27 4 79 5
1 7 200 26 30 99 98 19 32 225 .09 .36 5 79 5
1 7 300 27 30 99 99 20 40 232 .1 .46 6 80 7
1 7 400 28 30 99 100 19 34 230 .12 .58 8 84 8
1 7 500 27 30 99 98 21 40 228 .12 .7 8 82 8
1 7 600 28 30 99 98 21 38 231 .11 .81 9 84 9
1 7 700 28 30 99 99 22 45 230 .11 .92 10 85 10
1 7 800 29 29 99 99 24 48 231 .13 1.05 11 86 10
1 7 900 30 31 99 99 20 50 226 .06 1.11 11 85 10
1 7 1000 31 32 99 100 20 41 227 .12 1.23 0 85 10
1 7 1100 31 34 98 99 25 43 226 .06 1.29 0 85 10
1 7 1200 31 33 98 99 20 36 227 .03 1.32 0 84 10
1 7 1300 31 33 99 100 20 43 227 .03 1.35 0 83 10
1 7 1400 31 33 99 100 19 40 226 .04 1.39 0 82 10
Please Log in or Create an account to join the conversation.