Avalanche forecast

Hatcher Pass

Hatcher Pass Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The avalanche danger is LOW at all elevations.

The danger will rise to MODERATE at mid-upper elevations as northeast winds build throughout the day. Gusts are forecasted to be up to 35mph at upper elevations. 

With 10" of storm snow from the 11/25 pre-Thanksgiving storm available for transport, avalanches up to 1'-1.5' deep will be possible to human trigger on leeward aspects in terrain 30° and steeper as wind speeds increase. It will be possible for these to "step down" to deeper weak layers in the snowpack in isolated areas. 

Winds will diminish by Friday, but it will remain possible to find and trigger wind slabs formed today. 

Maintain good travel protocol and assess for signs of instability as you travel. Be on the lookout for drifting, stiff or hollow sounding snow under foot.

SPECIAL ANNOUNCEMENTS:

From all of us at HPAC, Happy Thanksgiving. Grateful for snow and for you! HPAC could not exist without the support of our community.  Thank You! Click HERE to support public avalanche information at Hatcher Pass.

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 UPCOMING EVENTS:

Tuesday, December 3rd – 6:15-8:00 PM @ Backcountry Bike & Ski

Join us for the first forecaster chat of the season aka the “State of the Snowpack” with HPAC forecasters. We will go over the new forecast platform, submitting public observations, a review of our season’s history and what to expect moving forward.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    With 10" of light, dry snow from the short but sweet 11/25 storm, we have ample snow available for transport. After enjoying a few days of calm conditions following our most recent storm, building winds throughout the day will be capable of moving snow and building slabs on leeward terrain. 

    Expect to find wind slabs 4-8" thick on southeast to northwest aspects (clockwise) on slopes 30° and steeper. With 24 hours of elevated winds in the forecast we expect the size and sensitivity of wind slabs to increase throughout Thanksgiving Day. 

    Look for signs of wind slab formation by observing blowing snow at and near ridgetop, feeling for changes in the snowpack (smooth /stiff/hollow) and observing shooting cracks, collapses or "whumphing."  These are most likely to fail on faceted, firm surfaces 

    Small tests slopes, pole tests and hand pits are great ways to test for stiffening of the upper snowpack and assessing slab characteristics as you travel. 

    (11/27/2024)

    Light-moderate winds expected with strong gusts possible today. 

    Photo: Hatcher Pass Avalanche Center

Avalanche Discussion

PERSISTENT SLAB:

It may be possible to find and trigger larger avalanches that will fail on old, buried and faceted weak layers within the snowpack up to 1-1.5' deep. This potential was observable yesterday where we saw 3 small human-triggered slab avalanches on Skyscraper on southeast aspects.

You are most likely to find this setup will be on previously wind-loaded slopes, southwest to north (clockwise) aspects, above 3500 ft on slopes 30 degrees and steeper in isolated and extreme terrain. It is possible for small avalanches within the new snow to "step down" and break into older layers.

In the last several days, we have seen some evidence of failure with this structure in tests in snowpits in snowpit tests from and small skier-triggered sluffs that have "stepped down" (see photo). In some instances these small sluffs have entrained snow down to our October rain crust just above the ground.

Although distribution of these persistent layers is variable and we have not seen much human-triggered activity on it, it may become more sensitive with an increased load from the additional weight of a skier and/or windloading. If caught unexpectedly in steep, tight, and extreme terrain, it could result in an unfavorable outcome due to buried rocks and an overall shallow snowpack.

DRY LOOSE:

While small and unlikely, it remains possible to trigger dry, loose snow sluffs, particularly in tight, steep features above 40°. On 11/27, a skier triggered an unexpected small sluff above Eldorado Bowl that entrained all available snow down to the frozen crust layer just above the ground. Several other skier-triggered dry loose sluffs were observable on Marmot and Skyscraper. For the most part, these sluffs have been small and managable, but it remains early season out there and a bad time to take a ride. In some areas, the snowpack is only 1-1.5' deep 

RECENT AVALANCHES:

Due to the poor visibility with the recent storm, we have not observed many recent avalanches or humans poking into much terrain. However, that all changed yesterday (11/27) when a calm, clear day plus 10" of new storm snow and the best skiing and riding conditions we have seen so far this season allowed for a more extensive foray into the forecast area for non-motorized users. We saw minimal natural activity minus some small mid-storm dry loose and storm slab releases.  While skiing and riding conditions were generally stable yesterday, we did see a few skier-triggered avalanches on 11/27. None were large enough to bury, injure, or kill. The biggest hazards are still shallowly buried rocks.

Regions covered