Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Sat
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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In sintesi

One to two feet of new snow and strong winds will make for very dangerous avalanche conditions today. You could trigger an avalanche on any slope steeper than 30°, especially leeward aspects receiving wind loading. Travelling below treeline requires extreme care. Near and above treeline travel in avalanche terrain is not recommended.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–3

    Yesterday, we saw one to two feet of new snow accompanied by extreme southwest wind near and above treeline, blowing 40 to 60 mph with gusts as high as 80 mph. An additional one to two feet of new snow will fall today with slightly calmer winds that are more conducive to wind slab development. The sensitivity and danger of this problem will rise throughout the day as two to four feet of snow will be available for transport.

    You are most likely to trigger an avalanche on southeast through north through west aspects, though you may find isolated areas of wind slab in aspects that are protected from the southwesterly wind, especially near trees, rock outcroppings, and along the sides of gullies.

    Identify areas where the wind has left its mark by pillows, drifts, and wavy snow surfaces. If you experience a hollow, drum-like sound or observe cracks shooting out from your sled or planks, you've found yourself a wind slab. 

    (2/14/2024)

    Ten foot shooting crack on a wind loaded slope

    Photo: Cory Beattie

  • Storm Slabs

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

    Rapid snow accumulations and low snow levels will allow for storm slab development below treeline. The lower elevation band provides enough shelter from the wind to make this problem more widespread than the wind slab problem. You could trigger an avalanche on any aspect steeper than 30° today. Actively monitor slope angles throughout your travels and watch for signs of instability.

Avalanche Discussion

By the end of the day, the forecast area will have accumulated two to four feet of new snow in the past 48 hours that the existing snowpack hasn't had time to adjust to. Travelling near and above treeline in the backcountry today is not recommended. Though do not fret, thanks to the low snow levels, there will be plenty of low angle powder to enjoy below treeline. Before you get out and brave the storm, check in with your group about mindset. Talk about how each individual approaches risk and what everyone's desires are, then adjust the group's desires for the circumstances and conditions. Try out the risk management flow chart in the media section and read more about managing risk in avalanche terrain in Roger Atkins 2014 paper, Yin, Yang and You.

The Everitt Memorial Highway and Castle Lake road remain closed for snow removal. Alternative access points include McBride Springs, the Nordic Center, Mount Shasta Ski Park, and Pilgrim and Deer Mountain OSV parks. You can ride a sled from FSR 31 (Old McCloud) up to Old Ski Bowl. Here's a map of the riding boundaries for the Southside of Mount Shasta.

Regioni coperte