Avalanche forecast

Rattlesnake

West Central Montana Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Another round of fresh windslab development is expected today with continued ridgetop winds. It will be possible to trigger avalanches anywhere the snow has blown into slabs 6 inches thick or deeper. Fresh wind slabs may hide older wind slabs from the past 72 hours and could break deeper than expected if triggered. 

Watch for red flags like shooting cracks, blowing snow, or fresh avalanches. If you see these, stick to slopes less than 30 degrees.

Avalanche problems

  • Wind Slabs

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

    Rattlesnake snow totals have come in less than forecast for the past 72 hours, but today is could recieve the most new snow with 4-7 inches possible. Periods of stronger winds during this multi day snow event have steadily built wind slabs on east aspects, along ridgelines, and crossloading in complex terrain. Expect the fresh wind slabs to be sensitive, and the older wind slabs to be more stubborn. 

    Wind slabs often form just below ridgelines, below slope convexities, and in cross-loaded gullies. Identify wind slabs by looking for pillow-shaped deposits and wind drifts.  Evaluate snow and terrain carefully as older wind slabs may be hidden by new snow. Avoid slopes over 30 degrees if you see signs of instability like recent avalanches, shooting cracks, or blowing snow. 

    (1/7/2026)

    A wind slab human triggered by cornice on an upper elevation east aspect

    Photo: Arden Feldman

  • Persistent Slabs

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

    Triggering a persistent slab avalanche is unlikely, but poor snowpack structure remains in isolated areas. Intermittent reports of buried near surface facets and facets around crusts have shown propagation potential in snowpit tests. No avalanches have been observed on these layers in two weeks, but as it continues to snow, the load on these layers is increasing and may reach a tipping point. 

    You are unlikely to see obvious signs of instability, like cracking or collapsing, before triggering a persistent slab avalanche. To identify areas where the problem exists, dig in the snow and look for weak snow surrounding crusts. If you find this and want to avoid the avalanche problem, stick to slopes less than 30 degrees in slope angle. 

    (1/2/2026)

    Snowpit on an east aspect at 7400 ft in the Rattlesnake

    Photo: Arden Feldman

Avalanche Discussion

There is still uncertainty around the persistent slab problem and its distribution. It is unlikely in areas like Lolo Pass where December rain events fully saturated the snowpack. As you move south to areas like the central Bitterroot, it is unlikely in areas like Lost Horse or along the Bitterroot crest where the snowpack is deep. At the same elevation at the mouth of the Bitterroot canyons, the snowpack is much thinner and areas with weak snow around a crust are possible. If you decide to dig in the snow, please let us know what you are finding. Snowpit tests are helpful but not necessary, even a photo of your snowpit wall helps!

If you would like to learn more about the near surface faceting process than formed this layer, and why it is so specific in its distribution, check out this article from the Avalanche Review and focus on the melt-layer recrystallization process. 

On January 5th, a snowmobiler was killed in an avalanche near Lake Tahoe. Our condolences go out to the family and friends. If we look at the preliminary accident report, we find terrain and wind slab avalanche size that resembles much of the motorized terrain in our forecast zones. We mention this as a reminder and learning opportunity that even short running avalanche paths can be dangerous if they bring you into trees or terrain traps. 

Let us know what you see by submitting an observation. We appreciate all observations, no matter how small, as our forecast area is large, and it helps us understand conditions across all zones. 

Ski and ride safe!

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