|Travel Advice||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.|
|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
Triggering a slab avalanche 1-2+ feet thick continues to be our main concern. There has been mostly quiet weather and lack of people triggering avalanches over the past week. However, in observations across the region the January 21st layer of buried surface hoar and a variety of other layers of weak snow continue to show signs of reactivity. Notably at lower elevations there are facets over melt-freeze crust that are also still showing triggering potential. Persistent slabs are becoming more difficult to trigger with time, but a large and unmanageable avalanche is still possible. Weak layers in the snowpack below your feet or snowmachine should not be forgotten. Red flags may not be present before a slope releases and it may not be the first person on the slope that triggers the avalanche. The most likely place to find this avalanche problem are slopes that have not seen significant traffic this season.
Deep Persistent Slabs: Keep in mind that there are deeper persistent layers that could ‘wake up’ if you find the wrong spot above 3,000′ in the Alpine. At these high elevations, old weak layers of facets and buried surface hoar sit in the bottom half of the snowpack. This structure is most pronounced in places with a thin overall snow cover, such as the South end of Turnagain Pass, the Summit Lake area and Crow Pass.
Lower elevation snowpit on Eddies showing more than one weak layer of snow present in the snowpack.
Wind Slabs: Watch for old wind slabs that could pop out on steep slopes. These hard slabs often break when you are out onto them. Steep rocky terrain where the slab is not supported from below is the most suspect.
Cornices: Avoid traveling under cornices and give them a wide berth on ridges, as they can break back further than expected.
Sunshine: It’s that time of year when we need to pay attention to the sun. On calm days the sun can heat up Southerly aspects enough to melt surface snow. This heating can also cause a slab sitting on a weak layer to become more reactive. Keep this in mind if the sun is shining and you are enjoying Southerly aspects later in the day.
Yesterday was mostly sunny above the valley fog. Temperatures at upper elevations climbed into the low 30Fs and due to the inversion stayed in the 20Fs in the valley bottoms. Winds were westerly 5-15 mph with gusts into the 20s.
Today will be mostly cloudy with temperatures in the high 20Fs to mid 30Fs. Winds will be light and easterly. There are snow showers in the forecast for this evening with 1-3″ of snow possible.
Tomorrow snow is likely in the morning. Due to warmer air there may be some “mixed precipitation.” Temperatures will be in the mid 20Fs to low 30Fs. Winds will be easterly in the morning and shift to the west in the afternoon. There is clearing in the forecast for Friday and then another shot of moisture and precipitation on tap for the weekend. From the NWS this morning: The progressive nature of the pattern will continue through next week, with front and lows rolling into the region every 1-2 days.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||27||0||0||63|
|Summit Lake (1400′)||22||0||0||24|
|Alyeska Mid (1700′)||23||0||0||55|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||28||W||9||25|
|11/27/23||Turnagain||Avalanche: Tincan Ridge||Schauer/ Stiassny Forecaster|
|11/26/23||Turnagain||Observation: Road report: Slide with dirt on Repeat offender||Anonymous|
|11/26/23||Turnagain||Observation: Pete’s North||Ben Sullender|
|11/25/23||Turnagain||Observation: Tincan trees||John Sykes Forecaster|
|11/21/23||Observation: Spokane Creek||John Sykes Forecaster|
|11/19/23||Turnagain||Observation: Magnum – PMS Bowl||Schauer/ Cullen/ Jonas Forecaster|
|11/19/23||Other Regions||Observation: Sunnyside/Penguin||Jose Ramos-Leon|
|11/19/23||Turnagain||Observation: Eddies||Andy Moderow|