Avalanche forecast

Mount Shasta

Mount Shasta Avalanche Center
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Avalanche danger

Sun
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Very dangerous avalanche conditions exist on all aspects and elevations across the forecast area. With over two feet of new snow in the mountains, the snowpack has destabilized. Natural avalanches are likely, and human-triggered avalanches are very likely. Step back, and allow the snowpack time to adjust to the newly added load. Travel on, near, or below slopes grater than 30 degrees is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    The combination of moderate-strong wind, and new snow has developed wind slabs across the forecast area. The two feet of dry, soft snow has been quickly transported onto leeward aspects, destabilizing the snowpack in any area the wind has blown. Expect to find these wind slabs near and above treeline on NW-N-NE-E aspects, with cross loading on W and SE aspects. Below treeline, wind slab instability could still be found in clearings, behind ridges, and on leeward terrain. If triggered, these slabs could break multiple feet deep, over a hundred feet wide, and run long distances into seemingly safer terrain. Peak sensitivity and instability will be this morning. Today, stay off of, and out from underneath slopes greater than 30 degrees. 

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5

    Since yesterday, over two feet of snow has fallen in the mountains. Storm slabs will exist anywhere the new snow has fallen. With 24 inches of new snow, peak storm slab instability will be this morning. Expect these slabs to trigger easily with skis, failing up to 2 feet deep, and hundreds of feet wide. Best bet is to stay off of, and out from underneath slopes greater than 30 degrees. Additionally, these avalanches have the potential to run long distances, into flat and treed terrain. 

Avalanche Discussion

The current winter storm system will continue to impact the Mount Shasta area till mid-afternoon. In the last 24 hours, the forecast area has picked up a significant amount of water weight. Currently, Mount Shasta City has recorded 2.5 inches of water in the last 24. In particular, Mount Shasta City detected over 0.2 inches of water PER HOUR, between 5 pm and 11 pm last night. As for snow totals, there is 24+ inches of new snow at treeline, and potentially more on the upper mountain. 

Yesterday, forecasters assessed the Gray Butte summit area in search of rising instability. During the outing, precipitation intensity increased, with moderate-strong southwest winds actively loading the new snow onto leeward slopes. Multiple D1 wind slab avalanches were intentionally triggered on test slopes. A pit was dug at 7,600 feet on a NW aspect. Upon inspection, forecasters found the dry, loose snow from Thursday underneath dense new snow currently accumulating. This has provided a slightly upside down snow structure and will likely contribute to the avalanche danger today. 

If headed into the backcountry, today is the day to double-check all your systems. Have a partner, check your transceivers' functionality, give steep slopes a wide berth, and verify slope angle before committing. 

Thank you to everyone who came to last night's Movie Night! The MSAC team had a ton of fun, and we're already excited about the next one.

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