|Travel Advice||Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.||Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.||Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.||Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.||Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.|
|Likelihood of Avalanches||Natural and human-triggered avalanches unlikely.||Natural avalanches unlikely; human-triggered avalanches possible.||Natural avalanches possible; human-triggered avalanches likely.||Natural avalanches likely; human-triggered avalanches very likely.||Natural and human-triggered avalanches certain.|
|Avalanche Size and Distribution||Small avalanches in isolated areas or extreme terrain.||Small avalanches in specific areas; or large avalanches in isolated areas.||Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.||Large avalanches in many areas; or very large avalanches in specific areas.||Very large avalanches in many areas.|
There are a variety of potentially dangerous storm related issues today. Caution is advised travelling in avalanche terrain, these conditions warrant careful route finding and conservative decision-making. We received a 6-8″ of snow that started falling in late the afternoon yesterday. We have now received over 3″ of water equivalent in the past week, equating to over 3′ of new snow in the Alpine. With the snow available to transport, winds over the past two days have created slab conditions on leeward slopes. An observer reported cracking in the upper 18″ on Seattle Ridge yesterday and triggering a small pocket of wind slab. This set-up may be more developed today and easier to trigger.
In addition, temperatures are rising and may result in an “upside-down” structure and instabilities within the new snow. This may be more pronounced in the lower elevation bands. This means there is the potential for both wind slabs from the wind loading and soft storm slabs from the warming trend of the storm.
The snow line may rise over 1000′ today resulting in rain on snow in the lower elevation terrain. This could add additional load and saturate the snow on the ground. Wet-loose avalanches may be possible.
Watch for Red Flags (signs of instability): cracking, whumpfing and recent avalanching are all signs that the snowpack is stressed. New snow and wind may be actively creating dangerous avalanche conditions today.
We have been continuing to monitor the layer of Near Surface Facets and Buried Surface Hoar since they were buried at the beginning of this stormy period. So far they have been unreactive. However, as the slab and the load on top of this layer continues to grow they are worth remembering. This is an added reason for caution today in avalanche terrain.
Yesterday was overcast, snow started in the afternoon and continued overnight, depositing 4-8″ of snow. Northeasterly winds blew in the 20’s and gusted into the 40’s. Temperatures were in the 20Fs.
Today snow is forecasted to continue in the morning transitioning to scattered snow and rain showers after noon. Temperatures will be in the high 20Fs to upper 30Fs. Winds will be Northeasterly 15-25 mph. New snow accumulation of 2 to 4 inches is possible today. Snow showers will continue overnight into tomorrow.
The low in the Gulf in conjunction with the occluded front will continue the pattern of unsettled weather in the area for the next few days with next stronger pulse of moisture forecasted for the weekend.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||26||7||.7||42|
|Summit Lake (1400′)||20||2||.2||15|
|Alyeska Mid (1700′)||27||4||.3||35|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||21||n/a||n/a||n/a|
|11/27/23||Turnagain||Avalanche: Tincan Ridge||Schauer/ Stiassny Forecaster|
|11/26/23||Turnagain||Observation: Road report: Slide with dirt on Repeat offender||Anonymous|
|11/26/23||Turnagain||Observation: Pete’s North||Ben Sullender|
|11/25/23||Turnagain||Observation: Tincan trees||John Sykes Forecaster|
|11/21/23||Observation: Spokane Creek||John Sykes Forecaster|
|11/19/23||Turnagain||Observation: Magnum – PMS Bowl||Schauer/ Cullen/ Jonas Forecaster|
|11/19/23||Other Regions||Observation: Sunnyside/Penguin||Jose Ramos-Leon|
|11/19/23||Turnagain||Observation: Eddies||Andy Moderow|