|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.
Observers yesterday were able to see more of the avalanche activity from the week long storm. There was evidence of a widespread avalanche cycle from Girdwood to the Hope Y. Some crowns from avalanches earlier in the storm were harder to see and almost covered up by subsequent snowfall and some were distinct and more recent looking. The size of avalanches varied from large destructive slides to smaller pockets. A few recent cornice falls were also observed. Of note, observers in Summit did not see slab avalanche activity in that area. They did mention a cornice fall in the Incredibowls and a couple of small loose snow avalanches.
|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
Today east winds are forecast to be elevated throughout most of day, blowing 15-35 mph with gusts into the 40s and 50s. There is plenty of soft snow available for transport and an additional 3-6″ forecast to fall during the day. This is a perfect recipe for wind slabs. Be careful around terrain where wind slabs typically form– near ridgetops, below rollovers, and in cross-loaded gullies. Pay attention to changing surface conditions and the snow becoming stiffer. Because of the active loading natural avalanches will be possible and being aware of what terrain is above you will be key as well. Watch out for cracks shooting out from your snowmachine, skis or board.
Storms slabs: Decent visibility yesterday afternoon allowed for a better inventory of natural avalanche activity from the storm. There was a widespread avalanche cycle across the forecast area with a number of large avalanches with deep crowns. Signs are pointing to the snowpack stabilizing after this storm but there is still a chance of triggering a slab that breaks deeper into the storm snow. This is another reason for careful travel today.
Cornices: Cornices have grown large and are looming over some terrain. Wind-loading today could tip the balance and cause a cornice fall. Limit time spent underneath and give cornices a wide berth along ridgelines as they often break farther back that expected. A cornice fall today could also trigger an avalanche on the slope below.
We have been tracking a layer of faceted snow associated with the 12/1 rain crust, which is now buried around 6-8’ deep, and exists at elevations up to around 2500’. We have not been able to confirm if any of the recent large natural avalanches released at this layer but the vast majority appear to be storm snow only. It is unlikely a person could trigger an avalanche on this layer at the depths it is buried from Girdwood through Turnagain Pass.
The snowpack is shallower in Summit Lake and observers are finding varied reactivity with tests on this layer. However, at this point data is trending towards triggering an avalanche breaking on this layer to be unlikely here as well. It may get a larger load and become more concerning. We will continue to keep tabs on this crust and any facet development in this area south of our forecast zone.
Yesterday: Skies started out mostly cloudy with snow and rain showers (to around 300′) in the morning. By mid-day skies became partly cloudy. Winds were easterly 10-20 mph with gusts into the 30s. Temperatures were in the 20°Fs at ridgetops and 30°Fs at sea level. Skies became mostly cloudy overnight with light precipitation starting in the early morning. Easterly winds bumped up a bit with gusts into the 40s.
Today: Skies will be cloudy with snow and rain showers (rain/snowline around 400′) and 3-6″ (0.3 SWE) of snow in the forecast. Winds will be easterly 15-35 mph with gusts into the 40s and 50s. Temperatures will be in the 20°Fs at upper elevations and 30°Fs at sea level. Rain and snow continue tonight and may be heavy at times, 4-8″ (0.4 SWE) possible. Winds remain elevated and temperatures cool slightly.
Tomorrow: Rain and snow showers continue with light southerly winds and temperatures slowly rising. A warm wet storm is expected to move into the region overnight into Saturday. Expect a warm and stormy weekend. Think cold thoughts…
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
*Seattle Ridge data from 3 pm – 6 am. Big thanks to the rime clearing crew!
|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
|Observation: Lynx creek