Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

Increasing winds are forming fresh slabs of wind-drifted snow near ridgelines, saddles, and in cross-loaded gullies. Look for signs the wind has been at work, including blowing snow, dense surface snow, and an etched or scalloped appearance. Cracking under your skis or machine indicates you have found a sensitive slab. 

Avalanche problems

  • Wind Slabs

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

    The southwesterly winds have returned after several days of snowy but mostly calm conditions. There is plenty of snow available for transport, and we expect fresh slabs to develop and thicken through the day. 

    These features will be thicker, more widespread, and most sensitive at upper elevations, where it is more likely you could trigger a slide. You may also find isolated slabs from recent stormy weather in sheltered terrain where an avalanche could be triggered.

    Today’s blowing snow and fresh cornice formation point toward areas with wind loading and elevated danger. Look for the tell-tale signs of a wind-affected surface, such as ripples or dunes. Cracking or collapsing indicates you have found an unstable slab, directing you to a lower-angle slope.

    (4/2/2023)

    A human-triggered wind slab avalanche just below a sparsely treed ridge, a prime location for wind slabs in the mountains today.

    Photo: Woody

Avalanche Discussion

Snowfall over the past few days boosted our low snowpack and improved riding conditions at all elevations. Surprisingly, the recent series of storms arrived without much wind, preserving light surface snow in most locations. 

Light to moderate southwest winds with strong gusts returned overnight and will persist through the day. Fresh wind slab formation will be the primary concern in the Whitefish and Flathead/GNP zones.  A storm slab problem remains in the Swan Range, with thicker and more widespread slabs found in wind-loaded terrain. 

The Swan Range was favored with 2.4 inches of SWE since Thursday, which resulted in a CONSIDERABLE danger rating on Saturday. A party visited the Swan Front and noted thin slab avalanches in the new snow that may have stepped down to the ground. They also saw evidence of wind loading and shooting cracks in the snow surface.

Observations remain limited, but the new snow seems to have bonded well with the old snow surface in many locations. Saturday, WMR ski patrol found limited evidence of surface slabs during their control routes. I visited the side country just east of the resort and found a generally soft, loose snow surface. Mike was in the Flathead Range, where, unsurprisingly, he found travel difficult due to the infamous Middle Fork alder fields. An experienced recreationalist traveled to southern Glacier Park, where he noted thin conditions, with just the past couple of storms comprising the snowpack. 

A potent and messy series of warm, wet, and windy storms is on tap to impact the Flathead tonight through Wednesday. Expect dangerous avalanche conditions to develop this week!

 

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