Avalanche forecast

Mount Shasta

Mount Shasta Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Dangerous avalanche conditions exist above treeline. Steady, moderate winds and new snow the past three days have added stress to the growing snowpack. Additional snow and wind today will continue to form wind slabs. Careful route-finding and decision-making are essential near and above treeline.

Avalanche problems

  • Wind Slabs

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

    Three days of steady 10-15 mi/hr winds and 30 mi/hr gusts from SE-S-SW-W aspects, coupled with more than 12 inches of new snow, have grown the wind slab problem near and above treeline. The additional stress of more snow and wind in both the past 24 hours and today's weather forecast, particularly NTL and ATL, have led us to increase the overall danger rating to CONSIDERABLE.  There is likely variability in the size and distribution of today's wind slab problem. The biggest source of uncertainty adding to today's forecast is limited data on how wind-drifted snow has been forming the wind slab problem, particularly ATL.

    Use clues like blowing and drifted snow, stiffened snow surfaces, and other wind-created surface textures to help evaluate which slopes hold wind slabs. Cautious route-finding and conservative decision-making are essential if traveling near and above treeline.

  • Storm Slabs

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

    The first big winter storm has been affecting the forecast area for several days now. There has been variability in the weight and moisture content of this new snow, with low-density snow Nov 30-Dec 1, moist snow and freezing rain Dec 3, dry snow Dec 4, and the 3-7" forecasted for today. This has causing us to add storm slabs to the list of problems for today's forecast. The presence of a widespread facet layer with some varied reactivity has added some additional uncertainty to the forecast.

    Steady snowfall and fog yesterday below treeline at Bunny Flat Trailhead.

Avalanche Discussion

Forecasters are continuing to evaluate and monitor an early but growing weak layer of facets near the melt-freeze crust from the Nov 9-29, 2022 dry spell. While this layer hasn't yet been affecting the Mount Shasta region, like it has for Lake Tahoe and the northern Sierra Nevada, this could potentially change with the added weight of new snow and sunny weather ahead. The biggest limiting factor for forecasters is limited data and observations. As you head out the next week skiing, riding, and recreating, help us out by looking for this layer and letting us know what you find by submitting your observations to the Mt. Shasta Avalanche Center.

Regions covered