|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 one photo this morning of a skier-triggered avalanche on the south side of Tincan Ridge yesterday. The avalanche appears to have failed on a wind-loaded convex rollover. With clear skies for the past two days, we have also seen the aftermath of many natural avalanches failing within the storm snow, with some deeper activity possible in the Placer Valley.
|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
It’s looking like we’ve got another day of quiet weather on the way today, and although we are keeping an eye on some deeper issues in the snowpack (see the Additional Concerns section below for more on this), our main concern for now is the possibility of triggering an avalanche in steeper terrain that has been recently wind loaded. The winds picked up for a few hours yesterday evening, and with 2-3′ of snow on the ground after last week’s storm, there is plenty of material available for building wind slabs.
Don’t let the quiet weather today catch you off guard- be sure to take the time to identify and avoid features that have fresh windblown snow on the surface. The most likely places you will run into trouble will be in steep terrain just below ridgelines, on steep convex rolls, and in cross-loaded gullies. Fresh wind slabs will feel more dense than snow that has not been blown around, and may give you warning signs like cracks shooting from your skis or snowmachine. Keep in mind, you will not always get warning signs like that even when the snowpack is capable of producing an avalanche. This is the kind of problem where you may be able to gain some insight by using small, low-consequence terrain features to test the snowpack before committing to bigger terrain.
The wind has done some work along the ridgelines, but there is still plenty of soft snow out there. Photo looking south into Warmup Bowl on the back side of Seattle Ridge. 12.02.2023
It’s still dark up there, but the Sunburst webcam is back! Big thanks to Claire Bicknell, Ben Cross, and Eeva Latosuo for volunteering time to get the camera back up and running.
In the highest elevations in our area, there may still be isolated slopes with weak snow on the ground. This layer only exists at elevations above 3500′, and is now buried 6-8′ deep or deeper, That makes it hard to trigger and even harder to identify. The only known avalanche that has failed on this layer was three weeks ago (more details here). At this point it is very unlikely you will encounter this problem, but it is big enough that it is worth keeping in mind. The most likely place to find it will be in steep, rocky terrain, where total snow depth tapers to a thinner snowpack.
Yesterday: We had another beautiful winter day yesterday with partly cloudy skies and high temperatures in the low to mid 20’s F, with lows in the low to mid 20’s F. Winds were light out of the east, picking up to around 10-15 mph for a few hours last night with gusts of 20-25 mph. We did not see any precipitation across the advisory area.
Today: We should see another day of quiet weather today, with some high clouds and light west to northwest winds. High temperatures will be in the high teens to mid 20’s F, with lows in the high teens to low 20’s F.
Tomorrow: A low pressure system passing well to the south should bring increasing clouds and a trace of snow during the afternoon. The rain line should stay down around 500 feet. Easterly winds should increase tonight at 15-25 mph, with high temperatures in the low 20’s to 30 F, and lows tomorrow night in the upper teens to mid 20’s F.
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′)
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