Avalanche forecast

Bitterroot

West Central Montana Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Triggering a large avalanche on buried weak layers remains possible.  The most dangerous slopes are upper elevation north aspects with buried surface hoar, but don't let your guard down on south aspects with buried crust/facet combinations.

You may not see signs of instability like cracking or collapsing before triggering an avalanche. Dig in the snow and look for weak sugary snow with a slab above. If you find this poor snowpack structure, stick to slopes under 30 degrees in slope angle to avoid the problem. 

The safest and best quality riding will be on low-angle slopes sheltered from previous wind. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Most upper elevation slopes, and some mid elevation slopes, have at least one weak layer buried below a 1-3 foot slab. These layers have produced natural and human triggered avalanches over the last week with D3 avalanches observed in Lost Horse and Seeley zones. 

    While the problem is at all aspects and elevations, the danger is not uniform across these same elevation bands or aspects. The most dangerous slopes where triggering an avalanche is likely are upper elevation north aspects. These areas have 2 distinct and reactive layers of buried surface hoar. This problem makes its way into the mid elevation band in the westside Seeley area, around Lolo Pass, and in other areas wherethe top portions of slopes are between 5500 and 7000 feet in elevation. Surface hoar is a particularly nasty weak layer that can remain reactive long after it gets buried and is responsible for many avalanche accidents across the west.

    As you move onto south facing or solar slopes, you will encounter buried facet/crust combinations. These layers have shown decreasing reactivity, but poor snowpack structure remains and snowpit test results still show potential for fracture propagation and avalanches. 

    To identify the problem, dig in the snow. If you find a slab of firm snow on top of weak or sugary snow, avalanches are possible. Surface hoar will present as a thin grey line that runs across the snowpit wall. If you find this, be especially cautious as surface hoar can produce avalanches on slopes down to 30 degrees in slope angle.

    You may not see any signs of instability like cracking, whumfing, or collapsing before you trigger an avalanche today. It will be possible to trigger avalanches remotely from below, above, or to the side of slopes. Just because you see tracks on a slope does not mean the slope is stable or incapable of producing an avalanche. In conditions like this, the 2nd, 3rd, or 10th rider on a slope can be the one to trigger the avalanche if they find the right trigger point.

    There are many south facing slopes that are melting out fast and do not have enough snow to produce avalanches. Avalanche danger is low or non existent in these areas.

    (2/28/2026)

    This recent, very wide persistent slab avalanche failed in the Lost Horse drainage on a N-NE aspect at 8,000'. It broke over 800 feet wide.

    Photo: Ben VandenBos

  • Wind Slabs

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

    Tuesday through Thursday, we saw large amounts of snow transported via wind with sensitive wind slab avalanches. Today marks the 3rd day of light wind and minimal wind transport. Those wind slabs that formed earlier this week are on the edge of transitioning into a persistent slab problem as they become more stubborn and any avalanche triggered on them is likely to fail deeper on a persistent weak layer. 

    For today, expect minimal fresh wind slab development but be on the lookout for older wind slabs as they can still produce an avalanche large enough to bury you. 

    Wind slabs can be identified by their smooth and pillow like appearance or firm and hollow feeling. They often form downwind of ridges, rollovers, and gullies. 

    Avoid the problem by sticking to slopes less than 30 degrees. 

  • Loose Wet

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

    Another warm day today, but with increased cloud cover from yesterday. There are many factors that can affect the timing of a wet snow cycle, but if you see rollerballs beginning to fan out and entrain snow into small wet loose avalanches, expect a wet snow avalanche cycle to follow. 

    Many south facing slopes have developed a stout surface crust that will need to break down today before we see a wet snow avalanche cycle. With the increased cloud cover, upper elevations are unlikely to see wet snow today. Most of the wet snow problems exist at mid elevation where we will see the warmest temperatures and still have enough snow for avalanches. Only very isolated lower elevation south facing slopes have enough snow to make an avalanche. 

    If you find yourself sinking into wet and unsupportable snow, it is time to move to more sheltered terrain out of the sun to avoid avalanches.

Avalanche Discussion

The snowpack is in a transition period right now as we move from high danger and very reactive conditions, to danger trending downward and more stubborn avalanche conditions. 

Don’t be fooled though, there is still a 1-3 foot slab on top of weak snow. A common theme for avalanche accidents across the US is on clear sunny weekends following a storm. Lots of people are out in the mountains competing for fresh turns and before long, people are riding out onto slopes capable of producing avalanches. 

The last storm ended on the 25th and was followed by two days of strong wind. During this time we saw a natural slab avalanche cycle occur. This natural cycle is over, but it gives us a good indicator that the snowpack is stressed, and it won’t take much to overload buried weak layers and create an avalanche. 

If you get out in the snow, take a minute to let us know what you see. Your observations are a key component to an accurate avalanche forecast. Information about avalanches, the amount of new snow and wind, and riding conditions are all very helpful. Thanks in advance for your time, we appreciate you. Click here to access the observation submission page.

There has been a steady stream of avalanche accidents both fatal and non fatal in the past two weeks. Have fun this weekend, but ski and ride cautiously.

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