|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.
Many observations over the last week have pointed toward a strengthening snowpack in the core advisory area. The exception to this appears to be North aspects above treeline as we’ve had reports of large avalanches in these areas over the last two days; most recently yesterday a skier triggered an avalanche and went for a 1,000’ ride on the north side of Magnum. Let’s not forget that we have seen 3-5 feet of snow in the alpine (consolidated to 2-3 feet) over the last week that fell on a myriad of different surfaces. Upper elevation north aspects are notorious for harboring weaker snow longer, which is exactly where surface conditions are best, but also where unstable snow is being found. Recognize that if an avalanche is initiated, it will likely be big and encompass at least the last week’s storm (2-3’) with the potential to step down deeper.
As days grow longer (gaining 5 min 44sec today!) and sunnier, the temptation to ski bigger lines and push further out from the road and into periphery areas is strong. With this, safe travel protocols become increasingly important. Expose only one person at a time on a slope and utilize good communication and true islands of safety.
Defying gravity seems an accurate term for some cornices right now. Given the last seven days of sticky snow and moderate ridgetop winds many of these have grown to full-curl. Some have failed (Pyramid West face and Todd’s run) but many have only grown closer to the breaking point. This is a much simpler problem than the aforementioned persistent slab because we can see cornices; and what we can see, we can avoid. Simply minimize time spent underneath and give these backcountry bombs an extra wide berth when travelling on ridgelines.
Hippy bowl ridge and large, curling cornice.
Daytime heating and light winds could be concern for wet loose avalanches on steep south and west facing slopes today. Generally slow moving, these are a different beast than a slab avalanche. Wet loose activity is generally of concern if the potential exists to push you off your skis and into a terrain trap.
Yesterday morning started out with an intense band of snow moving through Turnagain pass depositing a quick 2-4 € at the road. Temperatures warmed throughout the day and intermittent periods of sun through broken clouds proved enough to melt that little bit of accumulation by 5pm. On ridgetops, temps were in the mid 20’s, winds light to moderate from the northeast and intermittent snow showers added up to 3-5 € (above 2,000′) on the northern side of Turnagain pass.
Today looks to be the start of a clearing trend that will last through the weekend with no precipitation forecasted. Expect temps to be warm today (mid-30’s at 3,000′) and wind shifting to the north in the 10-20mph range as an outflow (off shore winds) regime sets up. Slightly cooler air will filter in tomorrow and through the weekend under clear skies.
|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: Bertha Creek
|Schauer/ Cullen Forecaster
|Observation: Magnum & Cornbiscuit
|Moderow / St. Clair
|Observation: Tincan Backdoor
|APU Snow Science I
|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