Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Increasing winds from the NW may build fresh shallow slabs in the afternoon. With all the low-density snow, sluffing can also occur on very steep slopes. Look for signs of instability such as shooting cracks or whumphing collapses, and consider the consequences before entering complex terrain. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    A bump in NW winds may begin to drift the low-density snow into shallow, but reactive slabs on exposed slopes by the afternoon. Look for blowing snow, sharp drifts, small cornices, and wind-rippled snow. If you observe active wind transport, steer around those areas on steep slopes. Loose avalanches, otherwise known as 'sluffs' may pose a threat in very steep areas. Plan your ride so that you manage your sluff in steeper terrain and remember to never ride on top of other people in this environment.

    Observers have noted sudden failures on a crust about 3ft down, and a 3.5ft deep avalanche likely ran on this layer above Blue Lake over the weekend.  If venturing up high, you might consider still avoiding complex and unsupported terrain because of this. You can dig down and use snowpack tests to check on this potential failure layer. Larger, deeper avalanches are unlikely, but they may not be out of the question.

    (12/12/2021)

    A natural avalanche above Blue Lake likely ran on 12/11/2021. Washington Pass

    Photo: Josh Cole

Avalanche Discussion

The area picked up a respectable amount of new snow on Monday night and another inch or two could fall Wednesday night into Thursday. Winds are forecast to increase Thursday afternoon into the night, and could easily move the low-density snow we currently have on the surface. Some small dry-loose avalanches were observed on Wednesday in the Liberty Bell area. On Tuesday, Forecaster Josh Hirshberg noted obvious wind effects on upper Kangaroo and some cross-loaded gullies above Pine Creek. Josh found results that indicated avalanches could occur on weaker snow grains above the crust that formed in late November, 30" down on a NW aspect at 7,300ft in Liberty Bowl. An observer east of Cutthroat Peak reported a large collapse on a southerly aspect near treeline on Monday. The deeper slab release in the photo above illustrates the type of avalanche that is possible. Check out Drew's observation from a southeast aspect at 6,500ft. on Monday.

Saturday was an active day on Washington Pass with many natural avalanches reported up to size D2.5. Avalanches were reported in the Hairpin Valley, the Cutthroat paths (Highway 20, just south of Cutthroat Creek), and the Blue Lake area (see above photo). 

Régions couvertes