Bollettino valanghe

Bitterroot

West Central Montana Avalanche Center
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Pericolo valanghe

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

Conditions are generally stable throughout the forecast zone, however, low danger does not mean there is no danger. While it is becoming less likely, it is still possible to trigger a persistent slab avalanche on north aspects at upper elevation. 

Signs of instability like cracking and collapsing will not always be obvious. Dig down and if you find weak sugary snow beneath a slab, stick to low angle slopes under 30 degrees. 

Small wind slabs are possible today in areas where new snow has drifted into areas like gullies or couloirs along ridgelines. These avalanches are unlikely to be big enough to bury you, but any avalanche with such thin snow cover will be a traumatic ride.

Problemi valanghivi

  • Persistent Slabs

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

    It is possible to trigger a persistent slab avalanche on facets buried 1 to 3 feet deep. The two layers of concern are depth hoar on upper elevation north and east aspects and a buried crust with surrounding facets in the middle of the snowpack. 

    Both of these layers are becoming less reactive as the slab above them becomes less cohesive. That does not mean they are trustworthy, however. 

    Collapsing, cracking, or whumpfs are signs of instability, but they may not always be present. Dig into the snow and look for weak or sugary snow beneath a denser slab. If you find this, stick to slopes under 30 degrees. 

Avalanche Discussion

Welcome to the 2023/2024 forecast season and happy holidays from everyone at the West Central Montana Avalanche Center. 

Despite being the end of December, we still have an unusually shallow snowpack in all zones and with it, a low avalanche danger. Why low danger with multiple weak layers and facets from top to bottom? The ingredients for a slab avalanche are a weak layer, a slab, and a trigger. Right now the snowpack is one big weak layer but we lack a slab in most areas. Even in areas with a slab, things are stubborn and becoming less reactive. This will change in the future if and when it does finally begin to snow, but for now, we are looking at generally stable conditions across all three zones.

On south aspects, conditions are much more variable with some areas melted down to dirt even at upper elevation. 

Persistent slab avalanches in isolated terrain are our primary concern right now, but small wind slabs in areas where the wind has drifted snow and created a slab are possible. These will be small and unlikely to bury you, but any avalanches with such thin snow cover will be traumatic. 

Early this morning we saw a rime event that affected most of our weather stations but unfortunately, last night's storm underproduced in snow. At this point, there are no significant storms on the horizon.

Snow depth is still insufficient to ski or ride at mid and lower elevations in many areas. Hazards such as buried stumps, logs, and rocks are widespread. Use caution while traveling in the backcountry. 

Please consider submitting an observation of what you see in the mountains. Even a simple photo helps forecasters better understand conditions and create more thorough forecasts.

Contact us here if you're interested in volunteering for a field day with the Avalanche Center. This is a unique opportunity to ski or ride with a forecaster and learn or grow your own snow and avalanche skills. 

Ski and ride safe!

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