Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Light snow and wind with slowly cooling temperatures will leave few avalanche concerns for Monday. On the most wind-exposed, highest slopes, you may be able to trigger small avalanches in the new snow. Continue to limit your exposure to large, overhead cornices and slopes with open glide cracks.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1

    Expect up to 4" of snow at upper elevations by Monday evening. Above treeline, there may be enough wind to form shallow drifts on leeward sides of ridges. New snow may fall on weak snow surfaces, like surface hoar. If you manage to trigger an avalanche, it could be dangerous near terrain traps such as over cliffs or gullies. Otherwise, avalanches should be small and easy to avoid. Steer around freshly drifted pillows of snow and steep, unsupported convex features.

    Rain and wet snow may fall to at least 4,500ft. If you find wet, weak snow, consider the consequences of triggering a wet avalanche at low elevation.

    (3/17/2023)

    Small, skier triggered wind slab avalanche on the N side of Mt Howard on Friday.

    Photo: Pat Riffie

Avalanche Discussion

Continue to minimize your exposure below cornices, glide cracks, and other overhead hazards. Over the weekend, observers reported a round of mostly small wet avalanches on steep, south aspects. Cooling temperatures and cloud cover limited wet avalanches on Sunday. An observer on Jim Hill found widespread surface hoar (2-3mm) on shaded, northerly aspects. 

On Friday, Matt Primomo went to the east side of the Chiwaukum Range on the eastern boundary of the zone. He saw a round of small wet loose slides occurring on east and south aspects. Most slopes were still cold in the morning with fresh surface hoar in many areas, but temperatures warmed by the afternoon. He found the Valentines Day Crust about 3ft below the surface on a NE aspect at 5,600ft, and weak snow underneath it all the way to the MLK Crust. This may have been the weak layer responsible for some of the deep slab avalanches noted below.

An impressive deep slab avalanche was noted from the West Face of North Chiwaukum on Thursday. This may have run on the 10th or 11th, similar to other reported D3 avalanches. A very large D3 natural avalanche occurred on the north side of Rock Mtn, likely on the 10th.  The crown was at 6,750ft, NE-NW, estimated at 6-10ft deep, 500ft wide and it ran approximately 1800 vertical feet. Two similar D3 avalanches were reported from NW aspects above treeline on Cannon Mtn in the neighboring East Central zone. These were suspected to have run on the Valentine's Day Crust but we haven't been able to confirm this. Between 2/28-3/6 we received reports of triggered avalanches, up to size D2, that likely ran on the Valentines Day crust, including one on a SSW aspect below Skyline Lake. 

Regioni coperte