|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.
Large plumes of blowing snow were present yesterday along all the tallest peaks around our region and strong Easterly winds are expected to continue today. Wind loaded snow could be on all aspects due to top loading and cross loading. These slabs will be hard and supportable and have the classic smooth pillow shaped look. Wind slabs could easily be located further down slope than expected and have the potential to fracture above you. Triggering even a small wind slab could have very high consequences especially in the upper elevations where there is also a potential for initiating a much larger and more dangerous deep slab avalanche. More on this below. Should you go into the upper elevations maintain a conservative mind-set and avoid big objective slopes including their runout zones.
Active wind loading as seen yestereday on Big Chief in the Seattle Creek area.
Variable surfaces are preseent throughout the alpine. Note the crossloading pattern including the pillowed shaped snow loaded along gullies on the SE aspect of Seattle Ridge
On December 20th, two skiers were approaching Pastoral and remotely triggered a very large avalanche from below. Luckily they were able to run from its path and avoid being caught. This is a very scary set-up that is likely not going away soon. Deep slabs are located in the upper elevations of our forecast zone, above 3000’, on slopes that did not avalanche during the early December storm cycle. The snowpack ranges from 3-5+’ thick and is sitting on weak basal facets. Observations over the last few weeks indicate this poor structure set-up is widespread across our region in the alpine elevations. This is a high consequence avalanche problem that is impossible to outsmart. Keep in mind:
Photo taken on Dec.21, the day after the Pastoral avalanche. Approximate route of where the party triggered this avalanche and retreated out of its way.
Photo taken on Dec.21st when strong winds started impacting our region. Note theNorthern Chutes on lookers left side have not avalanche yet and are actively loading snow.
Yesterday skis were partly cloudy with strong Easterly winds averaging in the mid 20’s with gusts in the 60’s. Warm air was observed at lower elevations mid to low 30F’s and temps in the mid 20F’s along ridgetops. No precipitation was recorded.
Today expect skies to be mostly sunny with Easterly winds elevated averaging in the 20’s with gusts in the 40’s. Day time temps at 1000′ are expected to be in the mid to low 30F’s and dip down to mid 20F’s overnight. High clouds are expected to move into our region tonight with a few flakes possible overnight.
Scattered snow showers are possible tomorrow, but little to no accumulation is expected. Temperatures are expected to range from 20F-30F. Winds should decrease tomorrow morning and remain Light from the East.
|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: 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
|Avalanche: Base of Seattle Ridge
|Troy Tempel, Thomas Lees, .Josh Bollaert, Damian Naquin