Weekend Avy Forecast

The NWAC just posted their weekend forecast - with the very warm weather forecasted,  they are forecasting a high probability spring avalanche cycle.  www.nwac.us/forecast/avalanche/current/zone/10/.  Bummer,  with the North Cascade Pass opening TODAY at noon, and all other mountains also beckonning to us! 
Stay safe.

Thanks for the heads up Gerry. Best curtail my tours to moderate terrain. Glad to see the sun but disappointed on the avy forecast. Time for some corn skiing.

Thanks Gerry.

Sounds like NWAC is anticipating a "Big Warmup" this weekend.

I wrote about this in my NSAS presentation in 2008. For those who missed it, here are my notes:

alpenglow.org/skiing/high-route-tips/part3-mush.html

It's possible to ski during times like this, but you have to choose very carefully. Timing and location are critical. Be careful out there....

That is an excellent article Lowell. Thanks for the link.

There was no instability or avalanche activity observed on the NE side of Mt Hood yesterday (Saturday 5/12). All day there was a decent breeze keeping things cool. May be a different story today though as at 7am Tline upper telemetry reported a higher temperature (51) than it had all of yesterday.

There was no instability or avalanche activity observed on the NE side of Mt Hood yesterday (Saturday 5/12). All day there was a decent breeze keeping things cool. May be a different story today though as at 7am Tline upper telemetry reported a higher temperature (51) than it had all of yesterday.

Skiing along the North Cascade highway was good on Saturday. The snow never got mushy and we observed no avalanche activity. I was told that Friday was even better. It seems like the warmup finally arrived on Sunday, but I don't know if it caused any problems. It seems like areas east of the divide are consolidating well.

Mt. St. Helens was issuing optional refunds to folks on their permits due to this NWAC warning. In spite of a brutal sun yesterday (5/13), the snowpack was very solid, in fact it was moving less than last year. There was a wide 1' crown of unknown age in one steep bowl but it had clearly not stepped down.

At 15:00 back at Lone Fir Resort a "bank sign" was reading 94 degrees (!!!!) and it felt like it too.

I didn't see much of any activity this weekend on the south side of Rainier either. Even Nisqually chute, which was BAKING during both days, didn't move much at all. Still not very consolidated, however.

Mt. St. Helens was issuing optional refunds to folks on their permits due to this NWAC warning.  In spite of a brutal sun yesterday (5/13), the snowpack was very solid, in fact it was moving less than last year.  There was a wide 1' crown of unknown age in one steep bowl but it had clearly not stepped down.

At 15:00 back at Lone Fir Resort a "bank sign" was reading 94 degrees (!!!!) and it felt like it too.

Great Ski on St Helens! I thought the stability was fine even while wearing a shimmering dress!

It looks like the warmup yielded results at some point:

I was skiing all over the Mt. Baker Ski Area yesterday (5/15) and got a great view of Mt. Baker and the Park Glacier.  Last Friday (5/11) I saw the great tracks down the Park; yesterday I saw a huge crown across the entire Park headwall and assume the entire thing had ripped over the weekend or on Monday.

Similar aspects further around towards the Boulder Glacier showed large crowns also.

"The heat is on..."

More to come or end of story?

It looks like the warmup yielded results at some point:

More to come or end of story?

The Baker area in particular had a bad weak layer that was deeply buried. Often it takes a few consecutive days of warming (in this case 12000' freezing levels) to get be results with deeply buried weaknesses.

Often it takes a few consecutive days of warming (in this case 12000' freezing levels) to get be results with deeply buried weaknesses.

I thought this message in yesterday's Mountain Conditions Report (This email address is being protected from spambots. You need JavaScript enabled to view it.) for the BC Coast Mountains was pretty interesting:

Hello All,

Just wanted to send out a Heads Up! Yesterday around noon a Size 3 - 3.5 avalanche crossed the Hurely FSR between Km 11-12. It came down from the east side of Green Mountain in an avalanche path that was a regular offender. The road had been cleared through previous avalanches in the same slide paths within the last couple of weeks.

What is special about this slide is that the slope is SE facing and has seen high temperatures for the last week, but didn't slide until yesterday. The difference yesterday was that the area received a little bit of rain from convective clouds. The gauge at Green Mountain only recorded one or two mm of precipitation, but local reports say there was more in isolated areas.

With the forecast for 10-20mm of precipitation this coming weekend take care out there. There is still enough snow to slide to valley bottom and block the road behind you. The slide on the hurley was reported about 6 meters deep.

Cheers,
Conny Amelunxen
MG

More to come or end of story?

I'm thinking the former after we get done with this:

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PORTLAND OR
240 PM PDT MON MAY 21 2012

ORZ011-013-WAZ019-222315-
NORTHERN OREGON CASCADES-CASCADES IN LANE COUNTY-
SOUTH WASHINGTON CASCADES-
240 PM PDT MON MAY 21 2012

...SIGNIFICANT MOUNTAIN SNOW THROUGH THE END OF THE WEEK...

A PROLONGED HIGH ELEVATION SNOW EVENT WILL TAKE PLACE THIS WEEK AS
A COOL SPRING PATTERN RETURNS TO THE PACIFIC NORTHWEST. SNOW
LEVELS WILL GRADUALLY SINK BECOMING 4500 FEET ACROSS THE SOUTHERN
WASHINGTON/NORTHERN OREGON CASCADES AND AROUND 5500 FEET FOR THE
CENTRAL OREGON CASCADES.

CASCADE PASSES WILL LIKELY SEE A COUPLE INCHES OF SNOW TUESDAY
EVENING AND OVERNIGHT WHILE HIGHER ELEVATIONS WILL SEE HIGHER
AMOUNTS. MORE THAN A FOOT ON NEW SNOW IS POSSIBLE ON THE CASCADE
PEAKS ENDING WEDNESDAY NIGHT WITH SEVERAL INCHES EXPECTED ABOVE 6500
FEET.

CLIMBERS AND OTHER BACK COUNTRY ENTHUSIASTS ARE ENCOURAGED TO
ASSUME WINTER WEATHER CONDITIONS WILL BE PRESENT FOR THE UPPER
ELEVATIONS. CONDITIONS WILL BE SUCH THAT AREAL RESCUE ATTEMPTS MAY
BE INHIBITED THROUGH THURSDAY BY CLOUD COVER HUGGING THE TERRAIN.

$$

NWAC has issued a special statement for the weekend:
www.nwac.us/forecast/avalanche/current/zone/13/

This time there has been more precip on the east side, too with .5" on Tuesday and then whatever they end up with from Thursday-Friday.