|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.
The combination of wind and new snow in the Alpine over the past few days has created potential for wind slabs on steep leeward slopes. Slabs could be 1-4′ thick. Look for recent evidence of loading in the terrain. Cornice formation and scalloped or pillowed snow are good indications of deposition. Watch for cracking and collapsing under the weight of your skis or snowboard. Listen for hollow sounds and whumpfing.
** We are still concerned with a layer of weak faceted snow that formed during the colder temps in early November. These facets exist in many areas at the base of the snowpack but we have not seen evidence that they are reactive. We have limited information about the overall distribution of this layer in the Alpine and continue to be suspect of it lurking below the recent storms.
Photo below is an image of the cross loading on the SE face of Seattle Ridge.
The snowpack received rain up to 2500′ in the last series of storms. Temperatures in the Alpine cooled off and created a rain crust. At Treeline and below in areas that have not frozen there remains the possibility for wet avalanches in steep terrain. Observers reported “mashed potato” snow conditions and boot penetration to the ground. Additional rain showers and temperatures above freezing at lower elevations today will continue to create a hazard where the snow remains saturated. If the temperatures drop the danger will be LOW. Watch for new roller balls, wet punchy “trap door” snow and “push-a-lanches” starting at your skis or snowboard.
Yesterday observers reported rain runnels and roller balls up to 2500′.
Photo: Runnels on the Tincan uptrack. Credit: Ted Grosgebauer
Rain and snow showers will continue in the region today. Some areas will see clearing skies. This system will dissipate as a ridge builds over Southcentral ahead of the next front appproaching from the Southwest. Temperatures will remain in the 30’s today and it is forecasted to gradually cool over the next few days. Winds will be light and Easterly.
|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