Lawinenlagebericht

Swan Range

Flathead Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

Dangerous avalanche conditions still exist. Warm temperatures and partly sunny skies will continue to produce large avalanches. Carefully navigate terrain today. Stay off of and out from underneath any steep slope.

Lawinenprobleme

  • Cornices

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

    A season’s worth of wind along ridgelines has built large cornices. Warming and a slight chance of moisture may weaken them. Any cornice that fails has the potential to trigger a larger more destructive avalanche, or send car-sized blocks of snow tumbling down the slope towards you.

    Minimize time spent below as these are notoriously unpredictable. Cornices can break further back onto a ridgeline than you expect. The best way to manage this problem is to observe them from afar.

    Looming schoolbus size cornices demand cautious travel.  Give them a wide berth both from above and below.

     

     Photo: Pete Costain

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    2–3

    Above-freezing temperatures and solar radiation will continue to test buried weak layers. Avoid traveling on steep terrain or in avalanche runouts. These weak layers can be difficult to identify in a snowpit. Any avalanche that fails on these layers will be large and consequential. Enjoy ridgeline travel and minimize time spent crossing runouts.

    Persistent Slabs can break wide and far. The buried weak layer is generally 2-4 deep and the associated amount of snow involved will be large.

    Photo: Adam Clark

  • Loose Wet

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

    Reports continue in all three ranges of Wet loose and Wet Slab avalanches. Common characteristics are steep and rocky slopes with direct sun. These are often gouging nearly to the ground and entrain a large volume of snow. Rollerballs and mushy snow are great clues of which slopes to avoid.

    Groomed trails or cross-country ski tracks that pass below steep terrain have been impacted over the last several days. Don’t linger underneath any steep and open slope.

    Terrain such as this leaves very little in the way of safe travel.  Loose wet often starts in steep, rocky terrain that is exposed to direct sun.

     

    Upper Snyder Headwall, GNP Photo: Jackson George

Avalanche Discussion

The party continues! Another day of warm temperatures is on tap and thus a continuation of elevated danger.

Keep your risk low by managing your exposure if you decide to grab one more day of sunshine in the mountains. Steep, upper elevation slopes have been the frequent flyers as far as reported large avalanches. These are running long distances and debris piles are certainly large enough to bury a person or vehicle. It is not uncommon to see debris running into low-elevation terrain that doesn’t have any snow left.

Overnight warm temperatures will likely pave the way for mushy trail breaking on any south-facing terrain, steering you towards shaded aspects. Maintain an awareness of what terrain is above you as you make your way through the mountains. Buried weak layers are widely distributed, yet highly variable in stability. This makes predicting the slopes that are of greatest risk very difficult. The last day of warm and dry weather could be just enough to destabilize the weak layers. 

Wet Loose avalanches will continue to plague our region today. Rollerballs the size of golf carts and tongues of debris over groomed trails have been reported in the last 3 days. Hustle if you have to travel below steep slopes.

 

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