Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Generally safe conditions exist as the snowpack refreezes. Travel with a partner and carry a beacon, shovel, probe, as well as the knowledge to use them. At upper elevations, further reduce your risk by avoiding steep roll-overs or slopes peppered with rocks.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3

    Although unlikely, a rider could still trigger a large and destructive avalanche several feet deep in locations where a faceted layer is intact and weak. Following an abnormally warm week and widespread avalanche cycle, these locations will be limited to the highest slopes facing Northwest, through North, to East. 

    The snowpack may or may not give you clear signs of instability, such as collapsing, before avalanching.  In areas where you do not find a stout surface crust, dig down and look for weak, sugary snow near a crust formed in December.  Reduce your risk of causing an avalanche on this layer by choosing slopes without obvious trigger points. These include convexities, scoured slopes with a thin snow cover, and rock outcroppings. 

    (2/1/2024)

    A snowpit on a north aspect revealed a 155 cm depth at 6650'. The entire pack was moist and capped by a thin, breakable crust. The blue arrow denotes what we believe to be the deteriorating 12/22 crust.

    Photo: Mark Dundas

Avalanche Discussion

Temperatures are cooling off. So too is the avalanche hazard. After a week of warm, upper-elevation weather stations finally fell below freezing last night.  Sites at middle elevations are right around freezing. We’ve dropped the wet slab problem to reflect decreasing meltwater in the snowpack. The persistent slab problem is still listed at upper elevations on shaded aspects to account for any slopes that were unaffected by this week’s warm-up. Recent observations of the Flathead crest suggest that even these high reaches saw warm temperatures and avalanche activity, though there is still some uncertainty due to challenging travel conditions.

Unfortunately, the forecasted snowfall for last night did not materialize as expected.  Noisy Basin, in the Swan Range, is the only station reporting an increase in SWE (0.3 inches), and possibly an inch or two of snow. With only a few inches of snowfall expected today, I don't anticipate there being enough fuel for new snow problems to affect the avalanche hazard.  IF you find more snow and wind than forecasted, you can expect thin and sensitive slabs of wind-drifted snow to form along ridges, saddles, and other prominent terrain features.  Consider moving to wind-sheltered, or less steep terrain if you find 8 or more inches of recent, wind-drifted snow. Note that winds may shift to northeasterly today along Highway 2, so you could find new slabs forming on slopes that are normally sheltered.

Although we are still collecting data, a widespread wet avalanche cycle happened in the past week. So far, the most dramatic and widespread slides appear to have occurred in the Swan Range near Condon. You can check out what has been reported in the avalanches tab on our observations page.

Connect with the community, learn about snow, and support our safety mission at the Flathead Avalanche Friends Fest, February 21-24.  Following this week's avalanche cycle, I'm more excited than ever to hear the US Geological  Survey talk about wet snow avalanches. Link to event page: flatheadavalanche.org/event/friendsfest

Regioni coperte