Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

You can trigger slab avalanches in areas of recently wind drifted snow. Moderate to strong east winds on Thursday built fresh slabs - in some places on less commonly loaded west aspects. Work around steep slopes where you identify wind drifted snow by traveling on lower angle, more planar terrain.

Avalanche problems

  • Wind Slabs

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

    Thursday’s wind event had unequal outcomes for the west slopes with some areas seeing minimal wind effect while terrain a ridge away got hammered. Natural and human triggered slabs were mostly limited to D1 in size but a few were larger. Some observers definitely backed off of steep convex terrain holding fresh wind slab. Alpine terrain generally saw more wind but some high peaks were spared. Wind affected snow and fresh slabs are probably more readily found the farther east you travel towards the Cascade Crest.

    Wind slabs will probably have a similar, scattered distribution Friday. Evaluate slopes on a case-by-case basis as some commonly loaded slopes could be slab-free while others will be a no-go. Wind slabs may be easier to trigger where they formed over a crust on solar aspects.

    Cornices and other clues that show the usual direction of wind loading - normally from the south and west - might not be useful to determine where fresh wind slab lurks. Instead look for recently scoured ridgelines with smooth, fat, or pillowy-looking drifts on the slope below. Test slopes and hand shears will help gauge wind slab reactivity and depth and can help you identify areas where they are easier to trigger. 

    (2/23/2023)

    A skier was caught and carried in this small wind slab on Thursday.  Crown visible in the narrow chute above tracks and debris.

    Photo: Trevor Kostanich

Avalanche Discussion

AVALANCHE FATALITY: COLCHUCK PK, EAST CENTRAL ZONE: READ THE PRELIMINARY REPORT HERE.

 

Natural and human triggered wind slab avalanches were observed Thursday on the west slopes but were less in number, size and extent than anticipated. Small natural and human triggered avalanches were reported from West North. Some alpine areas saw strong winds while others remained quite calm. Numerous human triggered wind slabs were reported from Snoqualmie Pass with at least one backcountry traveler caught and carried. Most reported avalanches were D1 in size. No observations were submitted from West Central

An NWAC Observer near Darrington found 1' of light density new snow over crust below treeline Wednesday. New snow layering was observed as right side up and danger from slab avalanches was limited to wind loaded terrain. 

Natural avalanches to D2 were reported from Snoqualmie Pass and West North on Monday with smaller human triggered wind slab and loose snow avalanches the theme on Tuesday. The outlier avalanche was a  large natural that ran over 3000’ from high on the south side of the ridge connecting Church Mt. and Excelsior Pass (West North) down to 1900’ and put a 10’ debris pile on Church Mt. Road.

Strong westerly flow during the last storm favored the western regions of the zone with over 6” of precipitation and many feet of new snow near and above treeline. Moving inland the White Chuck Tripod picked up about 2’ of new snow with slightly less at Stevens Pass. 

 

Regions covered