Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Highlights

Expect some potential to trigger small loose wet and loose dry slides on steep slopes. For the most part, the avalanche danger has eased, but warm temperatures could influence wet loose slides during the day. Use normal caution near hazardous areas like cornices, and on very steep terrain where even a small slide could prove consequential.

Avalanche problems

  • Loose Wet

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

    Warming temperatures are expected to moisten snow surfaces on all aspects at lower elevations. If you see rollerballs or moist snow surfaces, consider moving to lower-angled slopes. Theres a chance you could initiate 'pushalanches', and these wouldn't be pleasent to get caught in. Look for things like rollerballs, and fresh fan shaped slides during the day as hints of this danger. Northerly aspects hold dry snow, and you could trigger dry loose slides.

    Mid and upper elevation, shaded slopes are likely to remain dry during the day. Continue to check for cracking or wind stiffened snow that could indicate isolated wind slab potential at higher elevations or in the northern part of the zone.

    Example loose wet avalanche activity on the south face in nearby West North zone. Photo: Lee Lazzara

Avalanche Discussion

Near Washington Pass, observers have reported unreactive snow on steep terrain over the past couple of days. A crop of surface hoar to 6mm in size was widespread. On Friday, observers near Harts Pass reported a recent cornice fall that triggered an 18" deep, wide avalanche on an easterly facing slope near Harts Pass. This slide ran on a thin crust, and stepped down another few inches to faceted grains. The rest of the snowpack was facets to the ground. This is an unusual snowpack structure for the zone, but it's worth keeping on your mind if you plan to venture to this area, or perhaps the far eastern edge of the zone as well. 

Earlier this week observers reported a number of large (up to size D3) avalanches throughout the Highway 20, Washington Pass area. Crowns were mostly in north to east facing terrain, below cliff bands or in other wind-loaded terrain. Many of these appear to have run on February 7th. Almost 2 feet of snow accumulated from February 3-8th. Observers were able to trigger avalanches on the February 3rd interface just after the storm. On Wednesday, a triggered slide near the Lyal glacier stepped down to the new/old interface and broke into a large avalanche, 6,400ft, east aspect. Also last Sunday near Rainy Lake, Josh found planar shears at the Feb 3rd interface at a profile site near treeline.

There are a few layers that we've been tracking in the upper snowpack. Aside from the February 3rd interface, the Jan 5th surface hoar (about 2-3ft below the surface) had previously been widespread and problematic in snowpack tests. With time and rounding of the grains, this layer is likely gaining strength. At a profile on Sunday above Rainy Lake, test results indicated that the layer was not a problem for avalanches at that location. Elsewhere, especially in the eastern mountains, it could still be a problem with subsequent storms.

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