Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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

A warm day with clearing skies will bring wet avalanches to sunny slopes. It may be easy to trigger avalanches in the recent snow, especially where overnight winds form drifts at upper elevations. Give yourself plenty of safer terrain options, and be ready to stick to lower-angle and sun-sheltered slopes.

Avalanche problems

  • Loose Wet

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

    Wet avalanches could occur naturally as the snow surface becomes moist. After a cloudy start, clearing will allow the sun to warm the snow surface. Watch for roller balls and snow falling from trees as indicators that the snow is getting moist and weak. Moist snow surfaces and wet snow that slides easily are also good indicators that you could trigger an avalanche. Watch for natural avalanches coming from overhead slopes and hazards like falling tree bombs and cornices. You'll want to exercise caution near terrain traps like above cliff bands or tight gullies where a slide could push you into hazards. 

    (3/13/2023)

    Debris from a very large natural avalanche that occurred 3/13 in Tumwater Canyon, between Fall ck and Cabin ck.

    Photo: Matt Primomo

  • Wind Slabs

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

    Westerly winds will form fresh slabs overnight and should taper off by daytime on Tuesday. Watch for natural avalanches, cracking in the snow, and small test slopes that slide easily as indicators of instability.  While you may not see actively blowing snow, pay close attention to recent wind drifting patterns. Avoid steep leeward, wind-loaded slopes.

    Above treeline, avalanches could be bigger and easier to trigger. Wind slab avalanches may be less likely near treeline. While unlikely, a similar wind event last week resulted in a couple of very large, natural avalanches above treeline (see photo and Discussion below).

    (3/11/2023) A very large (D3) natural avalanche on Rock Mtn. Estimated 6-10ft deep, 500ft wide and ran apx 1800 vertical feet. Likely occurred 3/10. 6,750ft, NE-NW. Photo: Ryan Minton

Avalanche Discussion

On Monday near Lake Susan Jane, Brooke Maushund and Matt Primomo reported up to 6" of new snow, which was a bit heavy below 4,500ft, though generally well bonded to the new/old interface. Winds were strong enough to transport snow, especially above treeline. They reported that a few wet avalanches occurred on Monday, up to D1.5, and steep, south slopes had a thin sun crust from the 12th. 

On Saturday, observers reported a couple of very notable avalanches. A very large D3 natural avalanche occurred on the north side of Rock Mtn, likely on the 10th.  The crown was at 6,750ft, NE-NW, estimated at 6-10ft deep, 500ft wide and it ran approximately 1800 vertical feet. Two similar D3 avalanches were reported above treeline on Cannon Mtn in the neighboring East Central zone. We haven't been able to get snowpack information from these or similar locations above treeline for much of the season. 

Between 2/28-3/6 we received a few reports of triggered avalanches that likely ran on the crust buried around Valentine's day. On March 7th, Matt Primomo checked out the most recent of the avalanches on a southerly aspect below Skyline Lake. The crust is now about 5 feet below the surface and avalanches on it would be very difficult to trigger.

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