Lawinenlagebericht

Flathead Range & Glacier NP

Flathead Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Your best bet for a safer and higher-quality experience is to beat the heat and get out before surfaces begin to moisten. Rapid warming will increase the threat of avalanches on all aspects by this afternoon. Gloppy snow, rollerballs, and small point releases are your sign to reduce your slope angles and watch for overhead hazards. The warming temperatures may make triggering slides on near-surface weak layers more likely. 

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Be wary of traveling below rocky outcrops or steep terrain where large piles of moving debris can become difficult to manage. Gloppy snow, point releases, and rollerballs are clues that the snow is getting wet and prime for triggering. Be strategic when route planning today and keep a special consideration on your exit strategy. It will be easiest to avoid this hazard by timing travel to move across, or under steep slopes earlier in the day before temperatures warms the snow surface.

    (3/21/2022)

    Recent warm temperutures prompted roller balls on northerly slopes at mid elevations. These are a clear sign the surface snow is getting wet and losing cohesion.

    Photo: Mark Dundas

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Weak layers buried 1 to 3 feet below the surface are gaining strength. Snowpack tests over the past few days show unreactive results, and we have not received any report of collapses or recent avalanches in 5 days. HOWEVER, we're uncertain how or how fast rapidly warming temperatures will affect this problem. Take advantage of cooler temperatures this morning and get out before temperatures soar above freezing. If you hear or feel whumpfing collapses, the threat of triggering a slab on buried facets remains. This is your clue to seek out slopes less than 30 degrees.

    (3/21/2022)

    A clean fracture (CT15 Q1) on a persistent weak layer buried 50 cm below the surface, above the early-March atmospheric river crust.

    Photo: Mark Dundas

Avalanche Discussion

We will start off this morning with a generally stable snowpack. South and west aspects are locked up with sun and melt-freeze crusts. On north and east aspects, buried weak layers have shown signs of strengthening and stabilizing for the past five days. There are isolated slabs of wind drifted snow at upper elevations. These slabs are small and mostly harmless in size and trending towards unreactive.

Unfortunately, rapid warming this afternoon will increase the threat of avalanches and deteriorate the quality powder snow. Weather models show freezing levels rapidly climbing to roughly 7500 feet by late this afternoon. Expect north aspects to become gloppy and wet if temperatures do climb as high as forecasted. The refrozen surfaces on slopes that face south and west will take longer to break down today. I won't be surprised if we see a round of rollerballs and possibly some small natural wet loose avalanches on all aspects. 

The snowpack hates rapid change.  Warming temperatures change slab properties, which can lead to weak layers collapsing and producing an avalanche. This afternoon and tomorrow will be a good test for weak layers buried earlier this month. It may be a good idea to plan a route that reduces your risk to steep, avalanche-prone terrain on north-facing aspects late in the afternoon.

Temperatures will remain elevated throughout the week with the possibility of consecutive nights with no refreeze at upper elevations. Cornices, glides, wet snow avalanches... all of them may be on the shelves. Stay tuned for changing conditions.

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