|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 last known avalanches occurred on Eddie’s ridge during Thursday’s outflow event. These were on the smaller size, up to a foot deep, and failed naturally.
|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
For the seventh day in a row, wind slabs remain our main avalanche concern. A quick-moving storm brought around 4-6″ low-density snow to Girdwood, Turnagain Pass, and the Summit Lake area last night, with 8-10″ in Portage and Placer, and 12″ to Seward. Unfortunately, that snow was accompanied by strong easterly winds overnight, including a period yesterday evening where speeds averaged 36 mph with gusts to 59 mph at the Sunburst ridgetop weather station. Although the winds are calming down and the clouds are breaking up during the day, we are expecting the wind slabs that formed last night and early this morning to remain reactive during the day today.
It’s looking like it will be a great day to get out, and might even be sunny by this afternoon. If you plan on taking advantage of this weather window before things get stormy again later this weekend, be on the lookout for slopes that have dense, wind-drifted snow on the surface. Keep in mind, a reactive wind slab will not always be a pencil-hard slab; it may just be slightly stiffer than the snow you’ll find on a sheltered slope. If you notice cracks shooting out from your skis or snowmachine, take that as a serious sign that you’ve found a slope where you can trigger an avalanche. Wind slabs can be a little easier to assess as you travel than some other types of avalanche problems. You can gain a lot of info by testing conditions on small terrain features, or taking a minute to step off the beaten path to do a quick hand pit and see if you find the telltale sign of stiff snow on top of soft snow. With a wind slab problem, it works out pretty well that the best skiing and riding will be in sheltered terrain, which will also be the most stable conditions.
Small test slopes like this one can be incredibly useful in assessing a wind slab problem. This was from Mary’s field day in the Front Range last week, but you can expect to find similar conditions across the advisory area today. 11.28.2023
There are two deeper weak layers in the snowpack that we are keeping an eye on. The first is a layer of faceted snow that is developing right above the crust that formed during the Thanksgiving storm, and the second is a layer of facets right at the bottom of the snowpack. It’s been three weeks since we saw an avalanche fail on the facets at the ground, and we have yet to see any avalanches failing at the Thanksgiving crust. However, we continue to get mixed results on that crust layer in our test pits, and we don’t want it to catch anyone off guard. If you’re planning on getting into bigger terrain, it would be a good idea to suss out that interface first.
Yesterday: Clouds built through the day, with increasing winds in the afternoon. All of the exciting action happened overnight, with 4-6” snow in Girdwood, Turnagain Pass, and Summit; 8-10” in Portage and Placer, and 12” in Seward. Winds peaked overnight with sustained speeds of 20-35 mph and gusts of 40-60 mph out of the east, and have since switched westerly at 10-20 mph.
Today: We might see another inch of snow this morning before this round passes, with clouds breaking up later in the day an a good chance of sun this afternoon. Temperatures will stay cold today, with highs in the single digits F and overnight temperatures hovering in the single digits to low teens F. Winds will back down during the day, from around 10-20 mph out of the west this morning to 5-10 mph out of the south this afternoon.
Tomorrow: Skies should be partly cloudy tomorrow with a chance for some light snow showers that might bring an inch of snow. Temperatures will stay in the single digits to low teens F during the day, dropping to the single digits above and below zero overnight. Winds should be light out of the west to northwest. Head’s up Seward- it’s looing like you could see another 8-10” snow tonight into tomorrow, with stronger winds during the day.
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