Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Dangerous avalanche conditions will persist on Thursday. Human triggered avalanches in areas of wind drifted snow are likely near and above treeline. Steer around steep slopes and seek out more sheltered terrain when you see blowing snow or fresh cornices.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Another round of snow and strong winds are on tap for Wednesday night. Wind speeds are forecast to back off on Thursday, but not before building  fresh wind slabs on leeward slopes. Identify areas of wind slab using visual clues like wind scoured snow surfaces and cornice features that point in the direction of wind loading.

    Large, steep, open slopes in the alpine are obvious terrain features to avoid. Poor visibility during storms and snowfall generally deters travel in this terrain anyway. Near treeline areas offer better travel, but you can still trigger a wind slab avalanche on steep slopes, especially those with convex breakovers or other trigger points. The best way to reduce your risk will be to simply avoid areas where you suspect wind slabs. 

    Blowing snow and fresh drifts help identify areas of  newly formed wind slab.

    Photo: Kyle Hornor

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The likelihood of triggering a small avalanche in wind sheltered terrain could increase during periods of intense snowfall on Thrusday . Though small, these avalanches still present a hazard in treed or rocky terrain and also in areas of thin snow cover.  Use caution around steep terrain features and use simple tests to evaluate the terrain ahead of you. Test slopes and hand shears can help you gauge slab reactivity in small, non-consequential terrain.

    Even small storm slab avalanches present a danger when combined with terrain traps.

     

Avalanche Discussion

A mix of rain and wet snow fell near treeline with 17” of new snow coming from 2.5” of total precipitation at Heather Meadows in the past 24 hours. Avalanche mitigation work this morning produced small avalanches in wind loaded terrain and avalanches involving wet snow at lower elevations. Another 1-2’ of snow is expected across the zone through Thursday afternoon with snow levels lowering through the day.

Reported avalanche activity was minimal since the natural avalanche cycle on December 18th. Human and snowmobile triggered wind slab avalanches were reported on the 19th at Mt. Baker and Canyon Creek.  Small loose wet avalanches related to clear skies and strong sun were reported the same day and also on Monday the 20th.

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