Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Watch for smooth pillow-like wind drifts in some unusual locations like west-facing slopes and well below ridgeline. You could trigger these thin slabs on slopes greater than 35 degrees. As the day heats up, seek out shadier slopes if you see new rollerballs or encounter wet sticky snow.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Strong east winds formed small new winds slabs in some unusual areas Wednesday. Look for smooth pillow-like drifts on westerly aspects, on slopes well below ridgeline, and along the sides of mid-slope features. You’re most likely to find new wind deposits in locations close to the Cascade crest such as Crystal Mt, Chinook Pass, and White Pass. While we don’t expect these slabs to be very large, you may trigger than quite easily and they could knock you off your feet. 

    Much older and larger slabs formed during Monday’s storm may still linger at higher elevations on N-E aspects. If you find firm hollow-snow, steer away from nearby steep terrain. While these older wind slabs should be hard to trigger, they could produce larger avalanches that break above you.

    (12/2/2020) Strong easterly winds transported snow forming new slabs in some unusual areas. Picture: Porter McMichaels, CMSP.

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Warm sunny weather forecasted for Thursday should reach all parts of the West-South zone. The snow surface formed this week may be firm and take longer to soften than normal. However, with temperatures well into the 40’s, we expect at least a few small loose wet avalanches. If you see new rollerballs or experience wet sticky snow, seek out shadier slopes. You’re most likely to see wet snow on steep rocky slopes at any elevation. Increasing clouds in the afternoon could help reduce the loose wet avalanche hazard.

    (11/27/2020) Pinwheels at Mt. Rainier after rising freezing levels and the sun came out a few days after a storm. [S aspect 5400']

Avalanche Discussion

The West-South experienced two radically different worlds on Wednesday. In areas close to the Cascade Crest like Crystal Mt, Chinook Pass, and White Pass, cold easterly winds kept conditions downright chilly. Around the volcanoes and away from the crest, temperatures soared into the mid-40’s. The different weather from Wednesday could cause significant differences in avalanches problems Thursday. Look for the warm weather to affect areas near the volcanoes first. The snowpack in these locations should be relatively warmer and more susceptible to another hot day. 

A generally strong and deep snowpack exists around the West-South zone. The height of snow near treeline typically ranges from 4-6’ (120-180cm). We expect any avalanche activity to occur within the recent snow or on the new interface (11/30). Observations from the Tattoosh, Crystal, and White Pass areas Sunday reported surface hoar prior to this week's storm. Wednesday an NWAC forecaster confirmed surface hoar in a snowpit near Crystal. However, so far, we have not heard of any avalanches on this layer. If you dig in the snow on shaded sheltered slopes let us know what you find by submitting a public observation.

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