|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.
This persistent high pressure weather pattern is reminiscent of the in-laws that have stayed past their welcome. Sure everybody loves sunshine and mild temps for a few days or even a week, but we yearn for a change in house guests eventually. I think that most can agree that we are ready for rowdy Old Man winter to come and “crash the couch” for a bit this month!
In the meantime this high pressure is allowing the brave and adventurous among us to venture through the Forest, past the Alder-wall and high into the Alpine. For those that make it, rewards have come in the form of generally stable snow and soft surface conditions. That being said, pockets of instabilities may exist in the form of shallow wind slabs and loose snow avalanches.
Shallow wind slabs have been found littered throughout the advisory area in the mid and upper elevations. As most of the surface is quite soft (comprised of near surface facets or ‘loud powder’) these wind slabs are fairly easy to identify by feel as the surface below your skis will feel stiff or hollow. These older wind slabs are very likely to be small (<6”) and manageable if initiated.
Winds are expected to pick up today and intensify tomorrow and into the weekend creating more widespread (though still shallow) wind slabs and some bitterly cold wind chills.
Loose Snow Avalanches:
We’ve had yet another day of weather that has aided in loosening and faceting the snow surface. Sluffs on steep terrain, > 40 degrees is low in volume but fast moving. Anticipate this, manage it accordingly and it shouldn’t prove much of an issue today.
Loose snow sluffs are fast moving but managable. photo: Wendy Wagner
Calm, cool and clear describe yesterday’s weather in the Turnagain pass area. Inverted temperatures continued with single digits at the highway and low 20’s at ridgetops yesterday. Winds were light out of the west and as soon as you began climbing the Seward highway into Turnagain pass, the low-level fog parked in the Arm was a distant memory with blue sky abound above about 300′.
The potential game-changer today and into the weekend will be the onset of moderate northerly winds starting out calm this morning and increasing into the low 20’s by this afternoon/ evening. These winds are fueled by a tightening pressure gradient between a low in the Gulf and the dominant high pressure over mainland Alaska. Any wind today should act to scour out a mild temperature inversion and low level fog by this evening. Temps are expected to be reach the mid-20’s by this afternoon under clear skies.
Cold, clear and windy looks to continue through the weekend as dry offshore flow continues to dominate southcentral Alaska at least through Sunday morning. Expect wind chill values to be well below zero by tomorrow. The National Weather Service is hinting at a pattern change by mid-week next week as the Bering High moves west into Russia promoting southern flow and an increased chance of precipitation.
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
|Observation: Silvertip Creek
|Observation: Seattle Ridge
|John Sykes Forecaster
|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