|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.
We received a report of cornices failing naturally at upper elevations, where the combination of unseasonably warm temperatures in the 30s to 40s F and sunny skies are causing them to weaken. The large cornice failures triggered localized avalanches where they impacted the slope below, but did not propagate to adjacent areas. In addition in areas where there is wind sheltered soft snow on the surface, dry loose avalanches have been reported to be a significant concern in steep terrain.
|Size (D scale)
|Unlikely to bury a person
|Can bury a person
|Can destroy a house
|4 & 5
|Can destroy part or all of a village
The potential for a glide crack to release and cause a very large avalanche involving the entire depth of the snowpack remains our primary concern today. Clear skies over the region should make it easier to identify existing glide cracks and minimize time spent underneath. Theses avalanches release at random times and can runout far into valley bottoms. We recommend avoiding them entirely if you can or travelling quickly while maintaining awareness of the slopes above if you can’t avoid travelling underneath.
In addition to glide avalanches we have received reports of cornices failing naturally. Cornices failures can be a significant hazard on their own, but they can also trigger avalanches on the slope below if there are any lingering instabilities that can be initiated by these massive triggers. Similar to glide avalanches, cornices can fail randomly and the best way to decrease your exposure to this hazard is to avoid spending time underneath large cornices. Especially if you note the temperatures are unusually warm and the sun is warming up the windward side of the cornice.
Finally, lingering wind slabs and dry loose avalanches could be a concern in steep terrain today. Small pockets of wind slab can linger on steep, unsupported features and cause small avalanches that can have large implications if you are in exposed terrain. Dry loose avalanches are also a concern if you are able to track down some wind sheltered soft snow on the surface. In steeper terrain these surface avalanches can pick up a head of steam and carry enough force to knock you off your feet. Best practice is to make a plan to manage your sluff before committing to steep terrain.
Yesterday: Clear skies and light NE winds averaging 5-10 mph with gusts to 20 mph at upper elevations. Temperatures were in the single digits F at low elevations and low 30s F at upper elevations.
Today: A high pressure ridge over the area will create continued clear skies and a lack of new snowfall throughout the region. For the first half of the day temperatures at low elevations are expected to remain in the single digits F and 20s to low 30s F at upper elevations. This afternoon the inversion is expected to become less dramatic, with temperatures at upper elevations decreasing into the teens F. Winds should remain light from variable directions with averages of 0-10 mph.
Tomorrow: Sunday looks very similar to the past couple days, except with colder temperatures in the teens F at upper elevations. Winds are expected to remain light and variable with averages of 0-10 mph. No new snow expected.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
|Bear Valley – Portage (132′)
|Grouse Ck – Seward (700′)
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
|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