|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.
We triggered multiple avalanches above treeline on Tincan Ridge yesterday. These were all relatively small, failing on slopes that were actively being loaded by the strong winds. See more details in this observation.
|Size (D scale)
|Unlikely to bury a person
|Can bury a person
|Can destroy a house
|4 & 5
|Can destroy part or all of a village
A storm system is headed our way, and is expected to bring strong winds and heavy snowfall our forecast area today and tomorrow. It is looking like the wind will be the key player for the daylight hours today, and although winds are light this morning they should ramp up quickly. With sustained speeds of 20-30 mph with gusts of 30-50 mph by later this morning, natural and human-triggered avalanches will be likely. These will probably only be 6-12″ deep at treeline elevations because of the limited soft snow on the ground, but could get much deeper in the alpine. The wind has shifted from the southwest to the southeast, so you might encounter unstable conditions on multiple aspects today.
Wind slabs tend form on convex rolls, below ridgelines, and in cross-loaded gullies. Be skeptical around any of these terrain features today, and be extra cautious if you start to notice cracks shooting out from your ski tips or snowmachine- this is a clear sign that conditions are dangerous. Sometimes you can recognize them from a distance because the surface may have a different texture, but other times they may be tricky to identify until you are standing on a stiffer snow surface.
For the very highest elevations in our advisory area (around 3500-4000′ or so), there is still a small chance that an avalanche triggered near the surface may step down to weak snow buried at the ground. This is becoming less and less likely with time, but we still have very limited info from that elevation band so it is a good thing to keep in mind if you are trying to get up high in the alpine.
Yesterday: Steady precipitation in the morning tapered off mid-day, with mixed precipitation at sea level and 2-4” snow at higher elevations. Winds were strong out of the southwest for most of the day, blowing 10-20 mph with gusts of 25-25 mph. Clouds broke up a little in the afternoon but skies remained mostly cloudy.
Today: A storm system is going to begin to impact our area today, with strong southeasterly winds ramping up this morning. Expect to see sustained speeds of 20-30 mph and gusts of 30-50 mph, with winds continuing to pick up tonight. Most areas will see only a trace of precipitation today, with rain levels rising to around 1000 feet as precipitation picks up tonight. Coastal areas like Seward and Portage could see around 0.5” precipitation today, equaling 1-4” snow. Skies will be mostly cloudy with high temperatures in the upper 20’s to low 30’s F and slightly warmer temperatures closer to the coast.
Tomorrow: We will see the bulk of this storm during the day tomorrow, with totals of around 10-12” in Girdwood and Summit Lake, and 18-24” possible in Turnagain Pass and Seward. Easterly winds are looking to remain strong throughout the storm, with sustained speeds of 25-35 mph and gusts of 40-55 mph. The rain line should hover between 300 and 800 feet, with temperatures in the mid 20’s to low 30’s F.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
|Bear Valley – Portage (132′)
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
|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
|Observation: Tincan Trees
|Moderow / Clayton