Boletín de aludes

Flathead Range & Glacier NP

Flathead Avalanche Center
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Peligro de aludes

Mon
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó last year. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Expect natural and triggered wet snow avalanches to occur after the surface crust thaws.  Warm and sunny conditions may develop slides in areas unaffected by yesterday's heat. Plan your day to avoid being below steep, sun-baked terrain, especially this afternoon. Move to a different slope if you find a mushy, unsupportable surface.

Our last scheduled daily forecast is Monday, April 7th. We will issue snowpack updates by 5:00 p.m. on Tuesdays and Fridays through April.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2.5

    Warm overnight conditions and today's sunny, above-average readings will result in another day of wet snow avalanche problems. Yesterday's sun cooked many slopes, especially on S-W-NW aspects, resulting in rollerballs and wet loose slides. Expect these wet snow problems to climb in elevation toward the higher peaks and possibly expand onto shady slopes.

    The overnight refreeze was substantially weaker than Friday night, but you should still find a surface crust this morning. As the crust breaks down, natural and triggered avalanches should be expected. Locations with dry snow becoming wet for the first time and slopes that didn't slide on Saturday will be most susceptible to natural activity. Loose dry slides may continue to be a nuisance on steep slopes where the surface remains dry.

    Warming temperatures are making the near-surface snow more cohesive. As meltwater production continues, this water could reach the late-March crust, approximately 1-2 feet below the surface, and increase the likelihood of a wet slab avalanche occurring today. 

    Plan your day to move off of and out from under sun-baked slopes when the surface becomes unsupportable and sloppy. Even small slides can pack a punch and push you into areas you'd rather not visit, such as tree stands, rock outcroppings, and gullies where the snow can pile up deep.  

    (4/5/2025)

    Multiple rollerballs and loose wet slides were observed on S-W-NW aspects of the Swan Front in the early evening on Saturday. Expect more of this activity today.

    Photo: Chris Gotschalk

Avalanche Discussion

Today (Sunday) will be the warmest day of the recent heat wave with temperatures climbing 5-10°F above Saturday's readings. We are starting the day 5-15°F warmer than yesterday morning, which will allow the surface to thaw sooner. This should enable loose wet activity to occur at higher elevations and affect slopes on the eastern side of the compass, potentially expanding to shady northerly slopes.

We are maintaining the danger level due to the poor refreeze and because today is only the second day of warming. Many slopes that were sun-baked yesterday underwent a natural avalanche cycle, and activity on these slopes should not be as extensive as yesterday. However, there remains plenty of terrain capable of producing loose wet slides, and, along with the uncertainty of wet slab development, dictates today's hazard rating.

Saturday's observations focused on the Swan Front, where widespread rollerballs and loose wet slides were observed. Activity reached into the upper elevations, topping out at 8,500 feet, near Condon, with slides up to D2 in size. 

Besides loose wet slides and potentially wet slabs, other problems that may develop today are also related to spring warming:

Glide avalanches: Warm temperatures and sustained sunshine may increase the chance of a glide crack failure as meltwater production continues. Cracks can be found on all aspects and elevations, but are concentrated on sunny slopes at mid-elevations, with the Swan Front a hotspot of activity. Glide failure is unpredictable, and the easiest way to manage this problem is to stay off of slopes beneath glide cracks. 

Cornice fall: Large cornices built from a season's worth of winds line many upper-elevation ridgelines. These features weaken and sag during spring warming.  A block tumbling down the hill could initiate a large avalanche on the slope below. Failure is unpredictable, so stay far from the edge of these as you travel ridgelines because they tend to break further back than expected. On sun-baked slopes, limit your time beneath these behemoths.

Grizzly Bears: An observer on the east side of Glacier dealt with a pesky grizzly that continued to harass their party despite multiple bear spray discharges. It's that time of year to reacquaint ourselves with being Bear Aware. Carry bear spray and know how to use it properly.

 

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