Avalanche forecast

Mount Shasta

Mount Shasta Avalanche Center
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Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

A large winter storm system will impact the forecast area by 12 pm today. The avalanche danger will start out minimal this morning, increasing drastically through the afternoon. Very dangerous avalanche conditions will develop by the end of the day. Natural and human-triggered avalanches are likely on all aspects and elevations. Travel in, near, or beneath slopes greater than 30 degrees is not recommended.

Avalanche problems

  • Storm Slabs

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

    This problem will develop as precipitation intensifies, likely in the late afternoon. With snowfall rates of 1–2 inches an hour, and total snow accumulation of 24–30 inches, the snowpack will quickly become overloaded. Peak instability will occur this afternoon through tomorrow morning. Storm slab avalanches will be widespread across all elevation bands. Large to very large avalanches could result, surely capable of burying and/or killing you. To avoid this problem, the best bet is to stay off and out from underneath avalanche terrain.

  • Wind Slabs

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

    In classic Shasta fashion, intense southwesterly wind will be accompanying the impending storm system. Strong-extreme wind speeds will exist across all elevation bands. With soft snow on the ground, and a lot more snow expected through the day, it won't take long for leeward slopes to become wind loaded. This problem will be reactive to skis, existing on NW-N-NE-E aspects, with cross loading on W and SE aspects. If triggered, these slabs could break multiple feet deep, running long distances into lower angle terrain. Wind loaded slopes will be particularly dangerous by this evening. To avoid this problem, the best bet is to stay off and out from underneath avalanche terrain.

Avalanche Discussion

After weeks of patiently waiting, a significant winter storm system has arrived to Mount Shasta. Today will start out relatively tranquil. As of 5 am this morning, wind speeds are light-moderate, and snow has yet to fall. However, this will quickly change. Most of the action will happen after 12 pm, with precipitation intensity of 1–2 inches per hour expected through the afternoon and evening.  By tomorrow morning, upwards of three inches of water, translating to 24–30 inches of snow will have fallen.

Today, the snowpack will rapidly destabilize, with wind slab and storm slab avalanche problems covering all aspects and elevations. If you're going into the backcountry, choose your mission and commitment level wisely. With weather and visibility deteriorating, over commitment to a lofty goal could get you into trouble. On transitional days like today, it's often best to go to an easily accessible area with lower angle terrain and defined escape routes. Consider exiting the backcountry early to avoid rising avalanche danger and poor travel/road conditions. 

To celebrate the return of fresh snow, come join the MSAC crew for a movie night! Tonight (12/13), we will be showing the 80's ski classic The Blizzard of Aahhhs at the Mount Shasta Community Building. There is a costume contest, so be sure to bust out your favorite 80's attire! Doors open at 5:30 pm and the film starts at 7 pm. $10 entry. 

Just a friendly reminder that the Castle Lake Road and Everitt Memorial Highway are CLOSED.

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