Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A slender snowpack down low and surface crusts higher up will keep avalanche concerns at bay through the middle elevations. Near and above 7,000 feet, several feet of recent snow have drifted into isolated wind slabs capable of causing harm, though reaching this terrain likely presents an equal or greater hazard. Travel will be arduous, with thin, wet snow barely covering the bush giving way to slick crusts higher up, so move slowly and keep plans flexible.

Problemi valanghivi

  • Wind Slabs

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

    As you climb higher, watch for signs of wind-drifted snow, such as dunes, ripples, and pillows. Cornices can help point to slopes below ridgelines that are typically loaded, which are the most likely locations to contain sensitive slabs today. Actively blowing snow or shooting cracks are clear warning signs—avoid nearby steep slopes.

    Slabs will harden and thicken with elevation. Between roughly 6,500 and 7,000 feet, some may sit on a slick crust, while higher up the crust thins or disappears altogether, allowing slabs to grow thicker. With recent warm temperatures and minimal new loading, many instabilities have likely healed. However, in complex terrain near ridges, tops and sides of gullies, and below cliff bands, be sure to assess for unstable snow before committing to steep terrain.

    (2/26/2025)

    A small wind slab triggered below a cornice. This is a great example of terrain where you could find the wind slab hazard today.

    Photo: Mark Dundas

Avalanche Discussion

Outside of light additional accumulations in Glacier National Park and the Flathead Range, the snowpack has received minimal new input over the past 24 hours, and avalanche danger is trending downward.

Reaching any avalanche hazard today requires navigating challenging snow conditions. Below roughly 5,000 feet, there is very little snow, so travel often means slogging through mud, slush, and brush. As you climb higher, a crust at or near the surface can support your weight, though in the transition zone, you may plunge into saturated snow beneath it. Higher still, the crust thins and disappears, and anywhere you find six or more dry inches of snow on top, wind slabs become possible. Snow professionals working for the BNSF railway observed non-reactive wind slabs above the crust up to 7,000 feet, and well described the current conditions.

Regarding the recent storm, here’s the good news. While heavy rain fell below 6,000 feet, there was little snow there to begin with. Up to 7,000 feet, rain occurred at times, but liquid water totals were much lower, and many stations actually recorded net gains in snow depth since Monday (Stryker +6”, Shed 7 +6”, Flattop +8”). To boot, in areas capped by a crust, this “new ground” helps limit avalanche concerns moving forward to new snow at or above the crust. If we can just get some low elevation snow, we will be in pretty good shape for mid-December!

Remember that above roughly 7,000 feet, multiple feet of snow have fallen, observations are sparse, and the overall snowpack structure beneath this recent snow is not fully known. If you get out to enjoy the great weather this weekend, please submit an observation to help paint a clearer picture for your backcountry community.

Regioni coperte