|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.
The last known human-triggered avalanche reported was a small wind slab pocket on Tincan, on Friday (12/1). Beyond that, we’ve seen evidence of a natural avalanche cycle that ramped up as last week’s storm was winding down on 11/30. Crowns were reported from Main bowl and Warm up bowl on the moto side of the highway to Sunburst and upper Bertha Creek on the non moto side.
|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
It was a pretty quiet weather day yesterday with light winds, cooling temps and no real precipitation to speak of. Given that lack of weather input, we dropped the danger rating in the treeline elevation band to LOW danger today. Low danger does not mean no danger and isolated areas below treeline still have the potential to nurture wind loaded pockets. However, the most likely places to find unstable snow will be in the alpine, above ~2.500’ where winds have redistributed last week’s fresh snow into shallow wind slabs. Below ridge lines , steep gullies or convexities where a slope begins to roll over into steeper (greater than 30 degree) terrain should all be seen as suspect and have potential to harbor wind slabs in the 1-2’ range.
This is a ’normal caution’ regime and while not an overly dangerous avalanche problem, keep in mind that skiing/ riding above terrain traps (trees, cliffs, gullies, creeks, etc.) amplifies the consequences should a slope slide. Keep eyes on your partners, communicate intentions and as always, be rescue ready.
Currently, the Summit Lake zone has a similar snowpack set up as the Turnagain area. Click on the video below for an update from new Chugach Avalanche forecaster Daniel Krueger who’ll be keeping tabs on, and issuing a weekend avalanche outlook for this area and points south on the Seward Ranger District this winter.
‘In this world there’s two types of crusts my friend. Those that prove problematic, and those that go dormant.’ — Quote adapted from The Good, the Bad and the Ugly
The Good: We’ve seen literally thousands of tracks on all aspects and elevations from skiers and snowmachiners testing the Thanksgiving crust since it was buried last week, with minimal avalanche activity. Snowpit tests results have been mixed but overall are showing the late November storm has bonded well to this crust.
The Bad: Crusts are notorious for ‘waking up’ down the road as the snow weakens and facets out above and below these layers. Buried crusts can often support a significant load before avalanching, or may just become dormant with time. Click here for some ‘Ruminations on Rain Crusts’ from our neighbors to the East.
The Ugly: This crust is quite widespread throughout the advisory area and has been found in all snowpits (up to 3,400’ and likely higher) over the past week. As such, if this layer becomes reactive it has potential to be a region wide problem, extending across multiple different zones and through elevation bands.
The Thanksgiving crust interface isn’t our greatest concern today, but it’s an obvious marker within our snowpack and one we’ll be keeping tabs on in the days and weeks ahead.
The snowpack in Summit Lake area and Turnagain Pass is quite similar right now with the Thanksgiving crust buried in the mid-pack and quite easy to suss out, even with a quick hand pit.
Yesterday: Mostly cloudy skies, light winds from the Northwest and falling temperatures made for a pretty quiet weather day. No new precip was measured in the core advisory area.
Today: We can expect mostly cloudy skies with the chance for 1-2″ of snow to sea level. Temperatures have fallen since yesterday with ridgetop weather stations reporting in the low teens F this morning. At 1,000′ temps are expected to be hovering around the low 20s F. We may see a slight bump in winds this afternoon from the Northwest before slacking off overnight.
Tomorrow: Temps will stay cool and winds calm with partly sunny skies in the morning. Clouds and light snow showers move in tomorrow afternoon as more active weather lines up ahead of the weekend. Any snow that does fall will be to sea level for the foreseeable future.
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