|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.
Recent snow in the higher elevations have fallen on slick and hard surfaces. While the snowfall amounts have been modest, the winds overnight have been transporting this snow onto leeward aspects, mainly West to North facing slopes. With temperatures forecasted to increase throughout the day, expect these slabs to become more sensitive to human triggers. Expect to see shallow pockets of windslab at mid elevations (up to 1800′) in open areas to be the most sensitive today, as these slabs have fallen on a firm crust and will heat up more readily than slabs in the higher elevations today. On the flip side, these slabs are not as large (<6″) as slabs in the upper elevations (>12″). Avoiding steep upper elevation starting zones which have a pillowy or wind affected look will also be important, as these slabs, once released, have the potential to carry people downslope and into terrain traps today.
It is important to not forget the poor structure of the base of our snowpack. Snowpit tests over the past week continue to show weak faceted snow persisting near the ground. The large dense slabs that formed over the holidays are now able to support a lot of weight. The chances of initiating one of these slabs is getting more difficult by the day. If you were to trigger one of these deep slabs, the outcome would be bad, as the volume of snow could be very large. We are clearly in a dormant period for this avalanche problem, as it has been a week now since any new deep slab activity has been reported. Unfortunately, the weak snow is being well preserved in many areas and will continue to lurk well below the surface for the forseeable future. Staying away from areas showing exposed rocks, ground or vegetation will be important in avoiding this problem today, as these are the most likely areas to trigger a deep slab avalanche.
In the past 24 hours Turnagain Pass has received ~6″ of new snow with .3-.5″ water equivalent. Winds have been moderate out of the E and SE averaging 20 mph with gusts to 36 mph. Temps, which have been on a steady rise overnight have averaged near 32 F at 1800′, and in the mid 20s F at 3800′.
Expect clouds to be on the increase through the day, winds out of the East 20-35 mph and a chance of precipitation with up to 3″ of new snow possible in the mountains. Temperatures will climb into the mid 30s F at 1000′.
The extended outlook calls for a greater chance of snow tonight, with precip continuing into the middle of this week.
Wendy will issue the next advisory, tomorrow morning January 22nd.
|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