Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Mon
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Above freezing temperatures and wet snow instabilities continue. As warming occurs throughout the day, you may find unstable snow on all aspects and elevations, most commonly on sunny slopes. Watch for roller balls as a sign of rising wet snow instability, give cornices plenty of room, and adapt your travel plans to changing conditions.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–1.5

    Last night was a warm one, with the Castle Lake weather station recording a low of 44° Fahrenheit and the weather station on Gray Butte recording a low of 39° Fahrenheit. Today will be slightly cooler, though mountain temperatures will still climb back up into the upper 40s to lower 50s.

    As the sun warms the surface, melt-water works its way through the snowpack, it can exploit any weak layers and trigger an avalanche that starts small and then grows as it entrains more wet snow moving downslope. These avalanches can be small yet mighty, as they could carry you over hazardous terrain such as a section of cliffs or down into trees.

    If you observe roller balls or if you're sinking deep into wet snow when you step off your sled, skis, or board, this is a big indicator that wet loose instability is on the rise. Traveling in avalanche terrain earlier on in the day will reduce your exposure to wet loose avalanches.

    (4/5/2025)

    Hula-hoop sized roller ball

    Photo: Cory Beattie

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    The warming trend from the past couple of days has weakened cornices and increased the odds of them failing. Most cornices around the forecast area are on the north and east sides of ridges, but because of differences in terrain and how the wind moves through the mountains, you could find them on any aspect.

    Cornice fall can be tricky to predict as they often fail without notice. This time of year, especially during warming periods, is when they are most likely to fail. The best way to prevent being crushed by one of these burgeoning beasts is to avoid or limit your travels beneath them, staying much further back from the edge of ridges, and keeping bare earth or trees between you and the edge.

    (4/4/2025)

    Cornice fall in the Seven Lakes Basin

    Photo: Samuel Clairmont

Avalanche Discussion

Yesterday's field observations revealed a small natural avalanche below treeline on a south aspect of Red Butte, small wet loose avalanches easily triggered by skiers on north and east-facing slopes below and near treeline on Gray Butte. Rollerball activity was widespread, with some growing to the size of a hula-hoop. By mid-afternoon, we observed a natural wet loose avalanche in upper Avalanche Gulch, running about 1,500 to 2,000 feet of vertical.

Wet snow avalanches (wet loose and wet slab) can be tricky to forecast in terms of timing, likelihood, and size. Sustained warming and rain-on-snow are the main triggers of wet snow instability. With precipitation this evening and a rain/snow line near 8,000 feet, we could see increased wet snow avalanche activity before the snowpack cools back down tomorrow. Watch out for changing conditions and limit your exposure to terrain traps.

The Everitt Memorial Highway and Castle Lake Road are currently closed to automobiles. The Siskiyou County Road Department currently lacks a functioning snow blower and is awaiting new equipment. Snow removal will begin as soon as possible.

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