New snow and wind have combined to create very unstable slabs, 1-3’ thick. Ridgetop winds from the East (SE to NE) picked yesterday afternoon and ramped up into the 40s and 50s mph overnight with several gusts in the 90s at Sunburst weather station. An additional 5-15″ of snow is forecasted for the higher elevations today and will increase the size of these slabs. These slabs will release naturally in steep terrain and could step down into older layers in some locations. Natural avalanches could run the full length of a slope, thus it will be important to avoid being near any runout zones today. Winds and continued precipitation will make natural avalanche activity likely throughout the day. There is some uncertainty with rain/snowline today. It is already 32F at Center Ridge and raining in Girdwood. Rain may fall as high as 2000′ today and the warming trend is forecasted to continue into tomorrow. Rain on snow will also increase the likelihood of natural avalanche activity at lower elevations. It is important to remember that the heavier, wetter new snow and/or rain is falling on lighter low density snow from Friday’s storm and loading a layer of buried surface hoar and small facets. Avalanche activity is expected at all elevations and aspects. This set up could be a hazard even in the Tincan Trees.
This is not a complicated situation. Avoidance of avalanche terrain is the only way to “manage” this problem today.
Sunburst Weather Station this morning. Strong winds and dramatic temperature increase. Note the gusting into the 90s.
Weak snow (facets and depth hoar) in the lower layers of the snowpack continues to be a concern in our advisory area. Today avalanches occurring in the upper layers have the potential to step down and release the entire snowpack in some places. If this does happen the volume will be large and could run long distances.
Travel in avalanche terrain is not recommended today including being in the runout of a steep slope, like in the flats below Seattle Ridge.
Question of the day: When will we reach the tipping point to activate these weak layers at the base of the snowpack?
Yesterday started out with clear skies in the early morning. Clouds moved in and precipitation started early afternoon. Snowfall and winds picked up around 2 pm with over a foot of snow falling overnight. Easterly (SE-NE) winds averaged in the 40s and 50s with gusts into the 90s. Temperatures dramatically rose throughout the day starting around 0F or single digits in the morning and rising to the high 20Fs to low 30Fs by late afternoon.
The storm continues today with another 5-15″ of snow forecasted at upper elevations. Winds will continue to be easterly 20-40 mph with gusts into the 60s. Temperatures will be in the 30Fs in the valleys and the high 20s at ridgetops. The mixing of cold and warm air with the system is causing some uncertainty about the precipitation type and amount. Rain/snowline is hard to determine. There may be rain up to 2000′ or higher or the cold air could stay in place and keep most of the precipitation snow. If you want to read more about it check out the NWS discussion this morning HERE.
The unsettled weather continues as another a wave of moisture is supposed to impact the area tonight into tomorrow. An additional 1-2′ of snow is forecasted but the temperatures and timing are still uncertain. Stay tuned and think cold thoughts…
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||25||9||1||66|
|Summit Lake (1400′)||22||2||.4||25|
|Alyeska Mid (1700′)||23||14||1||62|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||14||SE||25||59|
|12/03/20||Turnagain||Avalanche: Tincan Common Bowl NW Aspect 2900′||Matt Bethke|
|12/02/20||Turnagain||Avalanche: Tincan||Schauer /Johnston-Bloom Forecaster|
|11/30/20||Turnagain||Observation: Tincan- above treeline||Eric Roberts|
|11/30/20||Turnagain||Observation: Seattle Ridge Flats||Andrew Schauer Forecaster|
|11/29/20||Turnagain||Observation: Sunny Side||Peter Wadsworth|
|11/29/20||Turnagain||Observation: Overflight Recon Turnagain Pass||Silverton Mountain Guides|
|11/29/20||Turnagain||Avalanche: Sunburst||Alexa Dobson|
|11/29/20||Turnagain||Observation: Sunburst||Kathy Still|
|11/28/20||Turnagain||Observation: Tincan trees||Bob Lieberman|
|11/28/20||Turnagain||Observation: Tincan Trees||Tully Ward-Hamer|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: email@example.com
|Area||Status||Weather & Riding Conditions|
This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.