Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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

Look for signs of wind transport like scoured surfaces and stiffer snow to identify where you have a greater chance of triggering a slab avalanche. A weak layer found below recent new snow could produce avalanches at mid and lower elevations. Address signs of instability like audible "whumph" sounds or shooting cracks by moving away from steep slopes.

Avalanche problems

  • Storm Slabs

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

    A few feet of light density new snow, wind transport, and patches of weak, buried surface hoar should prevent total complacency in avalanche terrain. 

    Weak surface hoar buried on Dec 18th was found in a few areas around the Baker BC today. While not directly linked to any avalanche occurrences, it produced numerous whumphs in lower angled terrain on both shaded slopes and slopes facing the sun. If the snowpack starts talking to you take it as a warning and reassess travel on steep terrain around you. Even though the new snow over the Dec 18th layer appears soft and weak, it's still can release as a slab if the layer below is softer and weaker.

    Moderate winds will continue to build dense slabs over softer snow. New slabs will be found at or just below ridgelines. Though primarily small and stubborn to trigger, you may find larger more reactive slabs farther east towards the Cascade Crest where wind speeds could be higher Thursday. Assume greater danger where you observe blowing snow and active wind loading.

     

    (12/21/2022)

    Wind affected but still soft snow on Ptarmigan Ridge in the Baker Backcountry.

    Photo: Zack McGill - Cascade Mountain Ascents

Avalanche Discussion

Wednesday made for a mixed bag in terms of backcountry observations. No new avalanches were reported despite plenty of travel in avalanche terrain. On the other hand, some teams reported extensive whumphing at mid elevations. These signs of instability are likely related to surface hoar - buried Dec 18th - found in nearby pits. Most notable is that many of these reports came from south-facing slopes where surface hoar commonly melts away before being buried. On solar aspects surface hoar was found above a sun crust.

South aspects were observed to settle and thicken up a bit with full sun today but very cold temperatures likely prevented crust formation. Low density new snow made for small loose dry avalanches in steep terrain.  While wind slab formation was noted in more exposed terrain, they were unreactive when tested and produced no results, shooting cracks, etc. 

 

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