|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.
Approximately 3′ of snow or 3″ of rain has fallen in the advisory area since the storm started Tuesday night. This combined with strong ENE winds Tuesday through Thursday has created dangerous conditions in the mountains. Visibility was limited yesterday but fresh debris from a large natural avalanche was observed off of Seattle Ridge. The snowpack will still need time to adjust to this load today and allow the new snow to bond to the old snow surfaces. Elevated caution is advised. Slab depth, especially in wind loaded areas could be deep and very dangerous. Avoid slopes steeper than 30 degrees and be aware of what terrain is above you. Triggering a wind slab in leeward areas is likely. Look for patterns of wind loading, steer clear of stiff pillowed snow and watch for shooting cracks.
The warm wet snow combined with wind is prime cornice building conditions. Avoid travel underneath or on top of these today. They may easily fail naturally or under the weight of person or machine. When they fall they could overload slopes below and trigger a large avalanche.
A majority of the precipitation that fell on the snowpack in the Treeline elevation band (1000′-2500′) has been in the form of rain or very wet snow. This has created saturated conditions and the potential for wet loose and wet slab avalanches. This may change throughout the day as the temperatures are forecasted to drop. This could help stability increase as the snowpack freezes. On the flip side watch out for areas that receive direct sunshine (south facing) if skies clear, this may increase wet loose activity. We are at that point in the AK winter season where this will start becoming an issue. Avoid travel on steep slopes in this elevation band, especially areas where you could end up in a terrain trap.
Wet debris from Seattle Ridge. This avalanche ran almost into the flats near the motorized lot on Turnagain Pass yesterday.
Limited visibility yesterday made it hard to see how the glide cracks were behaving. The snowpack received extra weight and lubrication from rain and warm temperatures. This may cause increased glide activity and so may the cooling temperatures throughout the day. Glides are totally unpredictable. Avoid travel underneath them. We sound like a broken record as they have been in the forecast now for weeks however; they are really not something to mess with.
Yesterday skies were mostly cloudy with some clearing in the afternoon. Rain and snow continued to fall adding an additional .5″ of precipitation (5+” of snow above 1500′) to the snowpack. This brings our storm total to right around 3” of H2O (2-3′ of snow). ENE winds decreased throughout the day becoming calm overnight and temperatures were in the mid 20Fs @ 3000′ and in the mid 30Fs @ 1000′.
Today there will be scattered rain and snow showers mostly before noon with a clearing and cooling trend throughout the day. Winds will be calm and temperatures will be in the mid 20Fs to mid 30Fs. Tonight temperatures are forecasted to drop down into the teens and there is a chance for isolated snow showers.
Saturday will be mostly sunny as a stabilizing ridge dominates the weather pattern for the day. Clouds move back into the area overnight. Stay tuned for the next round of stormy conditions next week.
|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′)
*Sunburst anemometer has been down since 7 pm, 1/28.
|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
|Avalanche: Base of Seattle Ridge
|Troy Tempel, Thomas Lees, .Josh Bollaert, Damian Naquin
|Observation: Lynx creek
|Observation: Tincan Trees
|Moderow / Clayton