Bollettino valanghe

Bitterroot

West Central Montana Avalanche Center
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Pericolo valanghe

Wed
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Despite generally stable conditions, you could still trigger a persistent slab avalanche on isolated upper elevation slopes. Signs of instability like cracking and collapsing may not be obvious. Dig down, and if you find weak sugary snow beneath a slab, consider sticking to low angle slopes. In other areas, the primary hazards are stumps, logs, and rocks due to thin snow coverage. 

Problemi valanghivi

  • Persistent Slabs

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

    Triggering a persistent slab avalanche on upper elevation north and east aspects is unlikely, but not impossible. A poor snowpack structure exists where weak, old facets are buried 1 to 3 feet deep under a slab. 

    Without significant new snow, the sensitivity of the facets is decreasing as the slab above them becomes less cohesive. Obvious signs of instability, like recent avalanches, cracking, and collapsing, are becoming hard to find. However, that does not mean the snowpack is trustworthy. 

    Dig into the snow, and look for weak or sugary snow beneath a denser slab. If you find this poor structure, consider sticking to slopes under 30 degrees. 

Avalanche Discussion

Happy holidays from everyone at the West Central Montana Avalanche Center. 

Today, a small storm will deliver up to two inches of snow to the region with moderate southwest winds. This will do little to change the overall conditions. Unfortunately, there are still no significant storms on the horizon - Santa apparently ignored our wish lists…

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. We have weak layers, but we lack a slab in most areas. Even in areas with a slab, things are stubborn and becoming less reactive. Until more significant snowfall arrives, we are looking at generally stable conditions across all three zones. 

Persistent slab avalanches in isolated terrain are our primary concern right now. However, also stay alert for small avalanches in the recent snow in steep, upper elevation terrain. You could find small sluffs of loose snow or small wind slabs near ridgelines. Although they are unlikely to bury you, any avalanche involvement with such thin snow cover could be traumatic. 

Minimize your risk by using safe travel practices, like exposing one person at a time to steep slopes and always carrying your rescue gear. Remember, low danger does not mean no danger. 

Snow coverage throughout the forecast area is thin. Most SNOTEL sites show SWE amounts at around 50% of their 20-year medians, putting them near or at historic lows. Snow depth is still insufficient to ski or ride at mid and lower elevations in many areas. Upper elevations are variable, with thin coverage on south aspects and breakable crusts near the surface on north aspects. Hazards such as buried stumps, logs, and rocks are widespread. Use caution while traveling in the backcountry. While we wait for conditions to improve, now is a great time to get your riding partners together for some beacon practice. 

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