|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.
It has been just over 3 days since the tail end of the January 26th warm storm event added 2-3′ of snow to the upper elevations. This event overloaded a variety of weak layers in the pre-existing snowpack and caused a widespread avalanche cycle in the region. The good news is the snowpack in the heart of Turnagain Pass is showing signs of adjusting to the load, the bad news is other areas are not. This can make for difficult snowpack assessment as the weak layers of concern (depth hoar, facets and buried surface hoar) are lurking anywhere from 2-4+ feet below the surface. Thicker snowpacks, as found at Turnagain Pass and on the North end of the Pass had a stronger snowpack to begin with and this has been a big factor in the area beginning to adjust quicker. This is opposed to the persisting unstable snowpack found South of Turnagain Pass and the Girdwood Valley.
In general – this is a high consequence but low probability situation. If choosing to ride or ski the steeper terrain, we recommend using safe travel protocol, especially exposing one person at a time and grouping up in safe zones. If a large slab is triggered it may run further than expected and wrap around terrain features taking out mid-slope relative safe zones. Since the weak layers in question are fairly deep, it will likely take finding a thin spot in the slab or a big trigger to initiate an avalanche.
A few points to consider today if visibility holds enough for travel to the high elevations:
With Several inches of soft settled powder on the surface, watch for winds today to take this and form soft wind slabs along ridgelines and potentially cross-load upper elevation gullies. These fresh slabs could be sensitive to human triggers and likely to be on the shallow end, up to a foot thick. Watching for recent wind loading, stiffer snow over softer snow, cracks that shoot out from you and performing quick hand pits are all good ways to assess whether you have found a wind slab.
Winds have already impacted the Eddies ridge, to some degree, yesterday (photo: Andy Moderow)
For those traveling in the Seattle Ridge area, there are a few glide cracks opening up above the flats along the Northern side facing the road. There are also a few cracks on the backside. Watching for these and limiting time underneath them is recommended.
Glide cracks on the North side of Seattle Ridge (photo: Andy Moderow)
Mostly sunny skies filled the region yesterday before clouds began filtering through later in the day. Ridgetop winds were light to moderate from the West before switching to Easterly mid-day and remaining light with gusts near 20mph. Temperatures warmed a few degrees, into the mid teens F at all elevations yesterday.
This morning, we are expecting clouds to begin filling in as a frontal boundary heads our way associated with a low-pressure system in the Bering. Snow, falling to sea level, is expected to begin later today with only 1-3″ expected by this evening. Another 2-6″ of snow is forecast for tonight into tomorrow morning (also falling to sea level). Ridgetop winds will bump up today into the 15-25mph range from the Southeast and bump up again into the 20-35mph range overnight. Temperatures should continue to climb to ~30F at sea level, the mid 20’sF at the higher elevations.
For Tuesday into Wednesday, the front is expected to stall and weaken, this will bring a chance for another few inches of snow and decreasing winds. Later in the week, high pressure builds bringing clear sky conditions with cooler temperatures.
*THANK YOU to whomever cleared the rime off the Seattle Ridge weather station yesterday!!!!
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
|Observation: Silvertip Creek
|Observation: Seattle Ridge
|John Sykes Forecaster
|Observation: Kickstep NE Bowl
|Observation: TinCan Backdoor/ Center Ridge
|AAS L1 Turnagain
|Avalanche: Lynx Creek
|Observation: Turnagain, Seattle, Mt Ascension
|Silverton Mountain Guides
|Observation: Tincan Trees
|Dalpes/Thamm/ Schauer Forecaster
|Observation: Seward Highway across from Johnson Pass TH