Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 8 months ago.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

Highlights

Large avalanches are likely today in wind-drifted snow on steep slopes near ridgelines, saddles, and gullies. With fresh wind slabs at their most sensitive during and just after formation, today is a great day to enjoy excellent riding in sheltered terrain outside of the wind zone.

Avalanche problems

  • Wind Slabs

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

    New snow combined with moderate to strong, shifting winds has formed fresh wind slabs that a rider is likely to trigger. Avalanches will be most likely near ridgelines, below cliffs, at the tops of gullies, and in cross-loaded features. While slabs could exist on any aspect, the deepest are found on northwest through east to southeast-facing slopes. Expect slabs 1–3 feet deep, resting on a thin crust and capable of propagating widely and running long distances. These slabs will range from soft to hard, and may form farther down the slope and in terrain that is typically more sheltered.

    Textured surface snow, chalky drifts, and blowing snow are clear signs of recent wind transport, while recent avalanches or cracks shooting out from your feet or sled indicate unstable snow and a need to avoid nearby steep, wind-loaded terrain.

    While wind slabs are the primary concern, sluffs and small storm slabs are on the menu today in sheltered terrain and could carry consequences on treed or rocky slopes.

    (4/3/2022)

    This is an example of a slab avalanche in wind-drifted snow from a previous season. Note that this slab occurred beneath a corniced ridgeline on a drifted slope and was triggered by cornice fall or wind loading. This is the type of terrain where slides are most likely today.

    Photo: burket M kniveton

Avalanche Discussion

Cold temperatures and low-density snowfall have continued into Saturday, and the good riding from yesterday afternoon should be even better today. The best way to enjoy these conditions is also the best way to manage today’s avalanche problem: stay off wind-loaded slopes. While it may be tempting to poke into exposed terrain, all the ingredients for instability are present—new snow resting on a crust with moderate to strong winds actively building slabs. Natural avalanches are possible on very steep, exposed slopes, but human-triggered wind slabs are what’s on my mind.

Winds are expected to ease later in the day, and blowing snow may become less obvious, but don’t let that lull you into bigger terrain. With fresh slabs and cold temperatures, today isn’t the day for big lines.

On Friday, travelers near Whitefish Mountain Resort reported reactive small storm slabs. At the same time, we found less slab formation in the Northern Whitefish, though our day ended with periods of very high snowfall rates approaching 2” per hour and increasing wind speeds. Similar bursts of high precipitation intensity occurred again this morning and may redevelop later today, potentially increasing storm slab reactivity. That said, with mostly low-density, right-side-up snow, the problem most likely to ruin your day—and the one that should shape your tour plan—remains wind slabs. Winds have increased notably since yesterday, with clear signs of transport observed along the Swan Front and reported by the BNSF crew in the Flathead Range.

Your observations are super helpful to the forecast team and your backcountry community. Please keep them coming!

Regions covered