Boletín de aludes

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Peligro de aludes

Sat
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Generally stable weather over the past few days has allowed the upper snowpack to settle and stabilize. Wind slabs formed earlier in the week are stubborn and difficult to trigger. Upper elevations, above 6500', where the 12/7 rain crust is thin with weak facets beneath is where you might be able to find trouble today. Use caution when approaching consequential terrain with an eye for red flags like recent avalanches, shooting cracks or whoomphs.

Look for avalanche danger to increase in coming days as more snow is forecast to hit our zone over the weekend.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    The hardness and thickness of the upper rain crust varies across our forecast zones and has been found up to about 6,500 feet. Where the crust is around 2 inches thick or more, weak grains have been reluctant to fail in snowpack tests. Places where the crust is thinner and breakable, tests continue to produce failures with moderate to hard force. Your odds to trigger a deeper, more dangerous avalanche may increase as you move higher in elevation where the overlying crust is less supportive or non-existent.

Avalanche Discussion

Stable temperatures, light winds and no new loading events over the past several days have allowed the upper snowpack to settle and stabilize, allowing us to drop the hazard rating to Low at mid-elevations. The possibility of triggering a slab avalanche at upper elevations, above 6500', remains possible on the 12/7 crust/facet combo.

At mid and lower elevations, rainfall amounts last weekend were much higher than at upper elevation. In the wake of the rain event, a stout, knife hard crust around 2 inches thick formed across all aspects. On those slopes, the forecast staff reports fewer concerning failures in faceted grains above the November 23 rain crust, and those layers are slowly getting harder. The rain did a fairly good job of knocking down most of the larger Surface Hoar grains that grew during last week’s cool, dry period. However, the forecast staff has dug a few snowpits where these concerning grains are refrozen and upright. This setup is easier to identify where the crust is thinner.

At higher elevations, generally above 6,500 feet, the crust gets thinner and eventually becomes non-existent. In the Selkirk Mountains, the December 7 rain crust is significantly thinner, and the same faceted grains below are softer and more worrisome than in the West Cabinet and Bitterroot Mountains. While triggering a larger, more dangerous avalanche is less likely than triggering a shallow slide near the surface, anytime we have weak snow grains near the surface, traveling with an investigative mindset will help reduce your avalanche risk.

Just because it is stable today doesn't mean it will be the same tomorrow. Look for avalanche danger to increase with additional loading from incoming weather this weekend. Additional loading from new snow will stress weak layers within the snowpack. Give the snowpack time to settle and investigate for signs of instability before stepping out into consequential terrain.

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