Boletín de aludes

Flathead Range & Glacier NP

Flathead Avalanche Center
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Peligro de aludes

Wed
Alta montaña
1 · Débil
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 7 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Triggering a large avalanche remains unlikely. You are, however, likely to encounter a variety of other obstacles and hazards in your day in the mountains, such as navigating recent blowdown, a menagerie of crust surfaces, and driving to the traihead. Simple travel plans on a supportable crust will provide the safest and most enjoyable options.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1.5–2

    Steep slopes above 6,000 feet and shaded areas may still retain the structure for large avalanches capable of burying or injuring a person. The most concerning slopes are those where the top foot or so of snow is cohesive enough to form a slab, and a buried weak layer persists. Upper elevations in the shade, without a surface crust, are the most likely spots to find this problem.

    The possible scenario for stumbling across an unlikely spot could be like this:

    • You were traveling on a very stout (and miserably difficult) crust when suddenly you transitioned to a colder/shaded slope. The snow beneath feels skiable/rideable. You stop and dig a quick, hasty pit and discover there is 1-2 feet of dense, cold, dry snow that holds together as a cohesive block. Look around and make sure that the terrain you’re entering doesn’t have cliffs, gullies, trees, or other types of hazards below you. Think- IF the terrain you are planning on riding/skiing were to slide, would the runout be clean, or consequential? 

    A supportable crust underneath you is the safest way to continue enjoying the mountains today.

    Consider the consequences IF the unfortunate happens and you are caught in an avalanche. Terrain traps, timber, rocks, or roads could amplify the experience. 

    The terrain where you find the highest quality of snow right now is unfortunately the most susceptible to a slab over buried weak layer problem.

Avalanche Discussion

Well, it appears there is an end in sight to the sustained period of high and dry. Another day or two of moderate temperatures will continue breaking down buried weak layers, slow the faceting of the upper 8-10 inches, and give us time to prepare for a welcome change at the snow surface.

There have been recent reports of buried surface hoar in the Swan range and thin crusts with facets below in the Flathead/Glacier National Park region. Either of these could prove problematic once buried. 

In the Whitefish Range, the common thread is supportable crusts on south-facing terrain and thin, breakable crusts on the shaded aspects. Mike and Josh found shaded aspects at 7,000 feet on Stahl Peak that had no crust at all. Notably, the terrain with the best skiing quality is also the type that they closed due to avalanche hazard right now. 

While it has been two weeks since any reported avalanches on a buried weak layer, I’m continuing to manage my hazard by limiting the consequence IF caught and carried. I’m remaining firm on staying off slopes with these characteristics: a hard slab is present, I’m above 6,000 feet, and there are significant pieces of terrain that I don’t want to hit if trundled downhill. 

All of the reports from the last 7-10 days have done a wonderful job of painting the picture of what snowpack looks like as we head into a weather pattern change. The lingering Persistent Slab problem is unlikely to disappear immediately. Unusual weather patterns create a dynamic mountain snowpack and will continue to require thoughtful discretion while recreating in the snow.  

Educational opportunities:

1/29 and 1/31: Ladies human powered Introduction to Avalanches. Find out more here.

2/9 to 2/15: Motorized Level 2 Avalanche Course. Find out more here.

2/21: Human-powered Rescue Refresh Clinic. Find out more here.

2/26 and 2/28: Human-powered Introduction to Avalanches. Find out more here.

Submit your observations for a chance to win an ORTOVOX probe and shovel!

  • Open to all motorized riders (snowmobiles and snowbikes).
  • One obs per day, as many days/month as you can get.
  • Monthly drawing on the first of each month.
  • This month's prizes donated by @JESCOMontana

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