Avalanche forecast

East Slopes North

Northwest Avalanche Center
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Avalanche danger

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

Moderate and gusty winds should easily drift the snow into firmer and thicker slabs. You may see plenty of clues, but the blowing snow will be the most obvious. It can help you discern local wind patterns and anticipate steep slopes you want to avoid.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    A few inches of new snow will only add to the soft snow available for transport by the gusty winds. This should quickly build new wind slabs along exposed ridges, the base of cliffs, and maybe even mid-slope gullies. In general, these new slabs should be small, but they could trigger more easily where they form over a firm crust (southerly facing) or possibly weak facets (shaded slopes). 

    It might be hard to fully assess these new wind slabs during the storm. Assume the moderate winds and blowing snow mean wind slabs unless you can prove otherwise. If you see any cracking or feel firmer deposits on lower-angled terrain, steer away from nearby steeper slopes. Since this problem is growing throughout the day, expect wind slabs to only become more common and thicker as the day progresses.

    (12/8/2024)

    Example: Blowing snow will be the most in your face clue for newly forming wind slabs. 

    Photo: Andy Harrington

Avalanche Discussion

This isn’t a particularly potent storm for the East North zone. We expect most areas to only pick up 2-4 inches (5-10cm) of new snow. However, this should come in a relatively short, stormy window during the morning hours. While the winds could linger, precipitation should turn more showery in the afternoon. 

Just a few inches of new snow isn’t likely to wake up any of the older snowpack layers. Instead, it will likely just give us another interface (1/10) to track. Prior to this storm, a crust developed on steeper southerly aspects, while other slopes remained soft and dry. Near surface facets and spotty surface hoar were also observed on Thursday.

Several older layers still exist in the snowpack. The most consistent has been the 1/1 interface where surface hoar was buried by 4-6 inches (10-15cm). Snowpack tests have been inconsistent on the layer. While we generally don’t expect this storm to change that, you can’t write off an isolated slab failing on this interface. 

An NWAC forecaster in the eastern portion of the zone found a generally strong and well settled snowpack. While similar to areas closer to the crest, he could see older layers and interfaces, none were particularly weak or concerning. Maybe the most notable recent event was a larger avalanche on Pica/Poster Peak on Jan 2nd. This slide highlights some lingering uncertainty, especially in rocky, complex terrain.

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