|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.
Yesterday was the second day since the surface hoar was buried on November 17th that we haven’t received any reports of human triggered slab avalanches in Turnagain Pass. With time this layer of buried surface hoar is becoming more stubborn and less reactive but this also means the slab has the potential to fracture once well onto the slope. This layer hasn’t gone away and still needs to be a major factor in slope choice. Remember buried surface hoar is persistent weak layer and human triggered avalanches are still possible. Observations around Turnagain pass continue to show that this layer is widespread throughout the terrain. Dozens of human triggered and remote triggered avalanches have occurred since November 17th on the popular slopes of Tincan, Sunburst, and Magnum. These avalanches have been small to medium in size; just large enough to bury a person or seriously injure you in a ride. Larger and/or steeper, more wind-loaded slopes that haven’t been ridden still have potential to avalanche and could have high consequences because of this weak layer. This is important to keep in mind today and throughout the weekend with more snow heading our way. Today new snow and wind increasing late in the afternoon may cause the danger level to rise. Pay attention to changing conditions, additional load will only make the consequences even larger. Be on the lookout for obvious signs of instability like blowing snow, shooting cracks and whumphing sounds. In addition new snow and wind will be loading weak surface snow (new layer of surface hoar and near surface facets) that has developed over the past few cold clear days and may be reactive at this interface as well.
With the holiday weekend there could be more people heading into the backcountry. Be extra aware of other groups above and below you and only expose one person on a slope at a time.
National Avalanche Center Danger Scale tutorial: HERE.
Buried surface hoar found easily in a snow pit on Tincan yesterday at 2700′. Photo: Andy Moderow
There were two glide avalanches reported on November 23rd and other glide cracks have been observed around Turnagain and Summit area. If you see a glide crack give these a wide berth, minimize time spent underneath, and remember these are totally unpredictable. They are not triggered by humans and are the entire snowpack releasing. These will also be hard to see when covered up by new snow and wind loading.
Glide crack opening on the face of Common Bowl on Tincan. Photo: Andy Moderow
…WINTER WEATHER ADVISORY FOR BLOWING SNOW REMAINS IN EFFECT
FROM 5 PM THIS AFTERNOON TO 5 AM AKST SUNDAY THROUGH TURNAGAIN
PASS AND PORTAGE VALLEY… See link HERE for more details.
Yesterday started with light snow in the morning with a inch of accumulation. Skies cleared in the afternoon and valley fog moved in late in the day. Temperatures were in the low 20Fs. Winds blew easterly in the 20s in the morning and shifted to northerly and light in the afternoon. Overnight the temperatures dipped into the teens and the winds were light.
Today will be partly to mostly cloudy as the storm approaches. Snow is expected to start this afternoon and winds are forecasted to pick up gusting into the 30s from the SE. 0-3″ of snow is possible. Temperatures should rise to the high 20Fs. Tonight the snowfall and wind will continue with 5-10 inches forecasted to fall and gusts into the 40s. Temperatures should remain in the 20s.
Tomorrow temperatures should dip back down to low 20Fs. Winds should become light and northerly and there is still a chance of light snow. There is a bit of clearing trend into the middle of the week and then more snow on tap for the weekend.
|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: 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