|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.|
After waiting for months, it seems winter is finally trying to show up. We have another storm system moving in today which is expected to add 2-6″ of new snow and another 2-6″ tonight – snow should make it to sea level. Avalanche conditions will bemostly related to how much new snow accumulates, however there are some concerning layers deeper in the pack to keep in mind (more on that below).
WIND SLAB and STORM SLAB:
Wind slabs forming on leeward slopes will be fairly shallow (4-8″ thick) today. Even in areas seeing little new snow, these should build due to 6-8″ of existing loose snow available for transport. With continued snowfall overnight, wind slabs could be in the 10-14″ thick range tomorrow – which will be more of a concern. Areas out of the wind, where up to a foot of new snow may fall by tomorrow, could see slabs as well. If you are headed out, monitoring the new snow with quick hand pits and/or using your pole to check for stiffer/denser snow over softer/weaker snow will be good ways to assess slab development.
LOOSE SNOW AVALANCHES (SLUFFS):
Natural and human triggered sluffs are expected in the new snow on all aspects and elevations. When the sun comes out, possibly tomorrow, watch for wet/damp sluffs on Southerly aspects.
Cornices will continue to grow and fall naturally with this warm(ish) storm.
The mountains are currently in a transition period from winter to summer which means a highly variable snowpack that changes dramatically with aspect and elevation. In short, Northerly slopes have weak faceted snow sitting anywhere from 2-8′ below the surface; this spread is so dramatic due to the snowfall amounts during last week’s storm. The South side of Turnagain Pass has a thinner snowpack and therefore these weak layers are more concerning. On Southerly slopes, a stout crust exists below the storm snow from last week (2-4′ below the surface). Initial bonding was poor and though stronger now, still a concern.
What this all boils down to is: triggering an avalanche that fails deeper in the pack, although not likely, is not out of the question. Remember your safe travel protocol: expose one person at a time, have escape routes planned, watch your partners and know how to effect a rescue if a slide is triggered.
|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|