Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

Ongoing sun and warm temperatures will maintain a concern for triggering wet avalanches. Continue to limit your exposure to large, overhead cornices. Falling cornices are difficult to predict and can be surprising and dangerous.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    During warming events, cornices can fall with little notice. Be aware when you're traveling near them and give them plenty of space. Stay well away from cornice edges when traveling on ridges.  Make sure places that you stop or re-group are free of overhead cornice hazards. A falling cornice can be dangerous on its own, and it could also a surprising avalanche. 

    (3/16/2023)

    Cornice fall over a recent skin track in Cutthroat drainage.

    Photo: Ryan Minton

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    You may be able to trigger them most easily at lower elevations, on west and northwest as well as east and northeast aspects. If you find, wet, weak snow that slides easily, move to lower-angle and more shaded terrain. Most sun-exposed slopes have already seen these avalanches and a subsequent freeze. Many shaded, north aspects are still holding cold, dry snow. 

    (3/19/2023)

    Rollerballs on low-elevation north aspects on Driveway Butte.

    Photo: Willie Webster

Avalanche Discussion

Andy Harrington went to Hart's Pass on Monday. He found frozen crusts on sun-exposed slopes and a decent-sized (D2) wet avalanche on a southwest aspect of Scramble Point. Around 7,000ft on an east aspect, he found an anomalously shallow area of snow (less than 3 feet) where much of the snowpack was well-developed facets. Over the weekend, observers reported lots of snow falling from trees and small wet avalanches on steep, southerly aspects. Even low-elevation northerly slopes warmed enough to form rollerballs. Clouds and cooler temperatures kept wet avalanches to a minimum on Sunday. Significant snowfall and intermittent wind events since late February added about 3ft to the snowpack. The current warming trend is changing the snowpack and has caused over a foot of settlement in less than a week at Washington Pass.

Three very large natural avalanches ran around the 14th above treeline; A D3 on an east aspect in Cutthroat Creek, and two D3s on  Big Kangaroo Peak, one on the northwest aspect and another on the northeast aspect into Willow Creek. These ran beneath large rocky cliffs. The slide in Willow Creek appears to have run down to the ground at a moraine, with a crown easily 3-6ft deep, possibly up to 10ft. 

The Valentine's crust is 3-5 feet below the surface in the western half of the zone, including near Washington Pass, the upper Silverstar drainage, and Hart's Pass. You can expect to find it closer to the surface at lower elevations and further east in the zone. There have been numerous observations and snowpack tests indicating weak snow and poor structure below this crust. It's suspected to have been a weak layer for some of the very large avalanches at the end of the last storm cycle. If you're motivated to dig deep enough, you can probably still find the January 5th surface hoar. We have less of an understanding of the progression of these layers east of Mazama and the Twisp River drainage.  

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