Avalanche forecast

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

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

Cohesive slabs of snow several feet thick sit above a mid-storm and older, deeper crust creating slippery sliding surfaces for these dangerous slabs to fail on. These slabs will be deeper on northerly and easterly-facing slopes, and if provoked could produce a slide that’s bigger than expected and more difficult to escape. Stick to lower-angled slopes while providing yourself an extra margin if near or adjacent to steeper slopes and avalanche paths while the new snow tries to find some equilibrium.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Since March 11, the Silver Valley-Bitterroot Mountains and East Cabinet Mountains received 2 to 3.5 feet of new snow. Increasing temperatures and fluctuating rain-snow elevations mid-cycle deposited a firm rain crust across the mountains up to about 5,600 to 5,700 feet in the East Cabinet and Bitterroot Mountains. Then, cooler temperatures returned and heavy snowfall quickly built another layer of cohesive slab above this harder interface. The recipe to trigger a dangerous avalanche quickly came together in addition to inverted slab layering below the mid-storm crust where softer layers are underneath harder ones.  

    With more time, these concerning storm interfaces will start to bond, but it could take longer than expected to heal. Areas below ridgelines, adjacent to rocky outcrops, and around convex terrain features are where winds likely enhanced slab stiffening and where these slabs may be more reactive. If the weather Sunday is sunnier or warmer than forecast, the new snow could quickly lose cohesion and start to sluff from steeper terrain on slopes that see direct sunshine.

    Since snowfall started on March 11, 2 to 3+ feet of snow has fallen across the Silver Valley-Bitterroots. The slab has come in inverted, with lighter snow at the bottom and denser snow on top, all sitting on a slick crust. Strong winds have further exacerbated the depth and sensitivity of slabs. 

    March 12, 2026. 

    Photo: Izzy Davis

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2.5–3

    A cohesive slab 3 to 5 feet thick overlies two buried surface hoar layers, with slab depths continuing to increase during the current storm. One surface hoar layer was buried at the end of January (1/28), and the other in mid-February around Valentine’s Day (2/14). The overlying slab has stiffened and settled due to wind, warmer temperatures, and natural settlement within the snowpack.

    As the slab has strengthened, the likelihood of human-triggered or natural avalanches has decreased. However, persistent weak layers always carry uncertainty, and these layers are currently being tested by rapid loading from the ongoing storm. If one of these layers were to become reactive, the potential remains for large to very large, destructive avalanches with serious consequences.

    The buried surface hoar from 2/14 and 1/28 is rounding and becoming less reactive, but can still be found 3 to 5 feet down. With these depths, triggering a Persistent Slab avalanche is less likely, but would carry significant consequences. These grains were from a northeast aspect near 6,200'.

    March 8, 2026.

    Photo: Izzy Davis

Avalanche Discussion

The last stormy period added a nice boost to the mountain snowpack and for the Silver Valley, it was the biggest storm of the season - and maybe the past few seasons too. Storm totals range 6 to 20 inches in the Purcells, 12 to 22 inches in the Selkirks, 24 to 37 inches in the West Cabinets, 38 to 40 inches in the East Cabinets, and 35 to 58 inches in the Bitterroots-Silver Valley. This amounts to 1.5 to 3 inches of Snow Water Equivalent (SWE) in the Selkirk and Purcell Mountains and 2.7 to 5 inches of SWE in the Cabinet and Bitterroot Mountains. The Lost Lake SNOTEL, just south of our southern forecast zone, in the St. Joe Mountains received a staggering 7.1 inches of SWE in four days.

At the onset of snowfall on March 11, the existing snow surface was very firm - slide for life firm. This was the product of multiple days of above freezing temperatures and light rain from March 7 to 9, then a strong cold front locked up the surface. We don’t know how high in elevation this hard interface existed before the last round of snow, but remote weather stations suggest the warming regime climbed well into our upper forecast elevation band to near 7,000 feet - maybe the highest peaks in the East Cabinet Mountains excluded.

Shortly after the storm delivered around a foot of snow, a warm tongue of air progressively drove the rain-snow line higher in elevation. This laid down an inverted slab over the old melt-freeze crust. Despite not being a prolonged event, the rain line early on March 12 climbed higher than expected and enough liquid fell to saturate the surface. Then a strong cold front along with violent winds helped plummet temperatures and the snow surface flash froze. This created yet another rain crust. Above the rain line, strong to extreme winds built a hard wind-packed interface. 

Fortunately, cooler temperatures graced the rest of the stormy period and several days of heavy snowfall added to overall slab depths increasing potential avalanche size. All said and done, we now have an upper snowpack with complex layering that could vary quite a bit across the same zones or neighboring areas. An avalanche that fails in the near-surface layer cake has increased chances to either take you for a long ride or carry higher consequences like a full burial. Slides that encompass entire start zones or adjacent terrain features still carry the threat to step down into one of two surface hoar layers that have trended more stubborn in recent weeks. These layers still sit patiently waiting for a larger trigger like a large Storm Slab avalanche, cornice failure, or rapid input from liquid water to fail.

Storm snow hazards are often elevated during and immediately after a storm. How long they linger usually depends on what the weather does. Does it stay cool or warm quickly? Does the wind continue to transport the snow onto leeward slopes helping thicken fresh slabs? Or does an anomalous amount of warm air and rain move in and saturate the recent snowfall? Well…some, part, or all of the above looks to happen over the next week.

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