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

Widespread wet snow instabilities will rise as warming occurs throughout the day. Wind slabs may linger above treeline where it's been colder and windier. Watch for wet snow surfaces, indicated by roller balls as a sign of rising instability. Keep an eye out for pockets of soft wind blown snow, especially if they feel hollow or exhibit cracking.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    As skies clear and temperatures continue an upward trend, the likelihood of wet loose avalanches will increase today on all elevations and aspects. Below and near treeline elevations hardly dipped below freezing last night. The longer the snowpack goes without a refreeze, wet loose instabilities will reach deeper below the snow surface.

    As 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.

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–2

    In the past three days, the Gray Butte weather station recorded moderate wind (17-25 MPH) with strong gusts (26-38), ideal speeds for blowing snow. As this spring warmup takes hold, lesser amounts of the new snow received in the last week remain available for transport. Above treeline on Mount Shasta, specifically at 10,000 feet and higher, significant warming has not yet occurred, and winds may have blown soft snow into slabs on leeward slopes, especially near ridgelines and in gullies.

    New cornice development, fresh wind drifts, and snow surface scouring (sastrugi) are all indicators that wind is influencing the snowpack. Feel for firm snow slabs over softer snow and look for the aforementioned indicators as you travel in the backcountry to aid you in identifying wind slab and avoid these areas of concern.

Avalanche Discussion

With six inches of snow settlement at the Old Ski Bowl weather station (MSSKI) in the past three days, new snow from the last week is bonding and avalanche hazard is on the decline. The wind slab avalanche problem is decreasing in likelihood as warming "locks up" any remaining soft snow and aids healing of the snowpack.

On an east aspect near 8,000 feet on Green Butte yesterday, a propagation saw test produced no result on this persistent weak layer and the temperature gradient showed a healing trend. A large, persistent slab avalanche released naturally on this buried layer of graupel earlier this week. Read the full observation here.

The Everitt Memorial Highway and Castle Lake roads are closed. Unknown re-opening.

Regioni coperte