Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Incremental snowfall and pesky winds continue to thicken drifted slabs directly below ridgelines and in gullies. Go around places with a smooth, rounded appearance and give a wider berth traveling below steeper slopes or convex rollovers. If you observe blowing snow or see cracking in the snow, retreat to lower-angled or wind-sheltered areas.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    New snow amounts around 6 inches combined with southwest winds have formed deeper slabs on northwest through north to southeast-facing slopes at mid and upper elevations. If the snow surface is stiff enough where you barely make an impression, your likely above one of these problematic slabs. Harder slabs of snow have potential to break above you and wider than you expect, so make conservative terrain-specific evaluations if the wind is dropping the new snow on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Incremental snowfall is slowly adding more stress to weak snow layers and faceted crust in the upper snowpack. The hardness and thickness of the early December rain crust varies across our forecast zones and has been found above 6,500 feet. Where the crust is around 2 inches thick or more, weak grains below have been more stubborn to fail in snowpack tests. Where the crust is thinner and more breakable, those same faceted grains have failed with less force in tests. Avoid shallow areas near exposed rocks or below cliffs where triggering a shallow slide may provoke a deeper, more dangerous slide.

Avalanche Discussion

Incremental loading has been the name of the game over the last couple of days. The snow globe shook hardest in the Selkirk and Cabinet Mountains where snow totals are around a foot deep, but all areas within our forecast zones received a nice surface refresh. Places where snow depths are around 8 inches or more, broader storm snow hazards are the soup de jour.

Be mindful of how steep a slope is regardless of which direction the slope faces. Fresh slabs may be deep enough that they could knock you over and take you for a ride. Even a small avalanche that stuffs you into a terrain trap can be dangerous. Monitor how conditions change as you move through the mountains and recognize that potential avalanche size increases alongside increasing new snow amounts.

In the Bitterroot Mountains and Silver Valley, the new snow has increased avalanche conditions, but you likely need a wind-drifted slope to find larger troubles. Leeward-facing areas below ridgelines and in cross-loaded terrain features are where hard slabs of snow likely lurk waiting for the extra push from a rider or machine before they avalanche. Fresh Wind Slab avalanches are typically more reactive while they form, so avoid steeper terrain where you see the wind actively loading the slope below. Use small test slopes to gauge sensitivity of the new or drifted snow before venturing into larger more open slopes at higher elevations.

On Saturday, snow safety teams in different mountain regions were able to trigger larger avalanches on heavily drifted slopes. Some broke deeper and failed in weak facets around a rain crust that was buried on December 7. While explosive triggered slides represent a bigger load needed to provoke a failure, it does demonstrate the lingering sensitivity of persistent weak grains below. Finding the shallow part of the slope or where the overlying slab tapers could mimic a similar response like a larger trigger in a fatter part of the slope with either a deeper or stiffer slab. Additionally, slopes with a hard slab or thicker crust above a weaker snow layer, it may take several people or machines descending the same slope before someone finds the “not-so-sweet” spot.

FIRST AVALANCHE FATALITY 2024-25:

We are saddened to report that the first avalanche fatality of 2024-25 occurred in the mountains northwest of Cascade, ID near Lookout Peak. A group of two snow bikers triggered an avalanche, and one was caught and fully buried. The slide was reported to be relatively small, but the rider was carried into a terrain trap and buried deeply. He was found with an avalanche beacon and extricated, but did not survive. The accident occurred just south of the Payette Avalanche Center forecast area. Our sincere condolences go out to those impacted by this incident.

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