|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.|
In terrain above 3,500’, the last storm cycle laid down mostly snow (as opposed to rain). Terrain above this elevation is harboring old wind slabs up to a foot in depth. These slabs are resting on weak interfaces. It is on steep upper elevation leeward slopes where you are most likely to encounter unstable snow today. The likelihood of triggering an old wind slab is on the lower end of the scale but cannot be ruled out.
We got a good observation from the Divide creek area yesterday. A shallow layer of facets is somewhat reactive to pit tests. Same for the well developed facets at the ground. Overall these are only moderate concerns, but should be taken into consideration when out in the backcountry.
Slabs 3-6 feet thick are sitting on weak snow near the ground in the upper elevations. It is less likely to trigger a deep slab today in comparison to a more shallow old wind slab or persistent slab. However, the possibility remains for triggering a slab that can pull out snow to the ground. Unlike the persistent (old) wind slab concern, deep slabs have the potential to move large volumes of snow. Avoiding likely trigger points, especially areas where slabs are thinner, will lower the likelihood of triggering a deep slab avalanche today.
This problem is not a concern below 3000 feet where the previously water saturated layers have now frozen into a very strong and stable crust layer.
In case you’re just tuning in, we have a very thick crust in the forecast area. This “bulletproof” crust exists on all aspects up to 3,500’ in elevation, and is over 2 feet thick in places. Travel in steep terrain warrants extra caution, as arresting a fall is very challenging at this time.
Expect all of these issues to remain until a shift in the weather pattern takes place and surface conditions change.
Clear skies, light wind, and average winter temperatures (20s F) have been the weather over the last couple days. This trend will continue through today and transition to something a little different this evening.
The National Weather Service is issuing a Winter Weather Advisory for Friday morning to Saturday morning for blowing snow that may reduce visibility and make travel difficult. This is due to a forecasted 2-6 inches of cold dry snow with moderate to strong wind.
|12/02/23||Turnagain||Observation: Seattle Ridge||Schauer / Keeler Forecaster|
|12/02/23||Turnagain||Observation: Tincan South Side||Anonymous|
|12/02/23||Turnagain||Observation: Eddies up track||Luc Mehl|
|12/01/23||Avalanche: Sunburst||John Sykes Forecaster|
|12/01/23||Turnagain||Observation: Eddie’s trees||Anonymous|
|12/01/23||Turnagain||Observation: Turnagain – God’s Country||Graham Predeger Forecaster|
|11/30/23||Turnagain||Avalanche: Tincan Trees||Kakiko Ramos-Leon|
|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|