Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

More clouds are in the forecast, along with lighter winds on Sunday. Near ridgelines, confined chutes, and the base of cliffs, you could still trigger an avalanche in wind-drifted snow. Stick to slopes less than 30 degrees where you identify deep drifts or wind-textured surfaces. In more sheltered northerly terrain, loose avalanches could knock you off your feet in very steep terrain. 

Avalanche problems

  • Wind Slabs

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

    Shifting wind directions formed stiff wind slabs on various aspects at mid and upper elevations. There have been consistent reports of wind slabs and long shooting cracks from the Washington Pass area. Before the new snow and increasing winds, snow surfaces may have harbored weak, faceted grains. These weak layers can often make wind slab instabilities last longer than usual. If you find fresh drifts that produce shooting cracks, steer around pillows and drifts on steep slopes. 

    Look for actively drifting snow, formations around trees and rocks, or stiffer snow surfaces to help you identify where you could trigger a wind slab avalanche. Areas near ridgelines or pronounced ribs may be especially prone to drifting. Slopes beneath large cliffs also tend to harbor slabs, as loose snow spindrifts off and accumulates below. You can use small test slopes to check how easily the snow fractures. However, with inconsistent distribution of these weak layers, these tests could be misleading. You can avoid the problem by sticking to well-supported or lower-angle slopes and seeking wind-sheltered terrain for travel. 

    Cornices are large, and you should avoid lingering underneath these monsters. They are a hazard just on their own but can also act as a large trigger and initiate an avalanche as they fall on the slope below. 

    Example windslab avalanche that ran on the 1/31 crust from last week. Copper Creek, SE, 7200ft

    Photo: Harry Keane

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    The past few days of very cold temperatures are weakening and faceting snow surfaces. With a stout crust below the recent snow, dry loose avalanches could gain momentum quickly. These loose slides may run naturally or be triggered by traveling in very steep terrain. They likely won't be very large but could still have high consequences in extreme terrain where a slip or fall could carry you over rocks or cliffs. 

    (12/11/2022)

    Example of dry loose avalanches in extreme terrain. 

    Photo: Marshall Baxter

Avalanche Discussion

Light winds and cloud cover will start off the day on Sunday. You could also see some light snow showers, and winds may begin to bump up a notch in the afternoon. 

On Thursday, the zone picked up anywhere from 3-6" of new, very low-density snow. Observers are reporting small ski-triggered and natural wind slab avalanches in alpine terrain every day for a handful of days, and that pattern continued on Friday. Professionals noted multiple small pockets of wind slabs that released naturally at upper elevations. 

Friday brought nice, sunny weather, and lower elevations now have a thin sun crust on the southern aspects. Temperatures were cold enough that higher elevations didn't see this same crust formation. On shady slopes, at mid and upper elevations, there is up to 1.5ft of recent snow over a stout crust from January 31. Lower elevations hold substantially less new snow over this crust, so travel may be challenging and slippery in some areas. A layer of faceted snow rests above the crust from January 31, and may be the culprit for the prolonged instability in wind-affected terrain. 

Snowpack information is limited outside of the Highway 20 corridor, including Harts Pass, the Chelan Sawtooths, and near and east of Mazama. If you get out into the backcountry, let us know what you find!

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