Lawinenlagebericht

Flathead Range & Glacier NP

Flathead Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Dangerous avalanche conditions continue due to warm temperatures, rain, and a weak snowpack. The avalanche danger will increase with elevation, where more snow exists. Being caught in a wet avalanche today may have a consequential outcome. Stick to low-angle slopes free of overhead hazards.

Lawinenprobleme

  • Loose Wet

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

    Wet avalanches may occur both naturally, or be human triggered today. Yesterday (Tuesday), Guy observed a wet upper snowpack and rollerballs in steep terrain at 7500 feet in the Flathead Range. Rollerballs are a precursor to wet avalanches. The best way to not be involved with wet moving debris is to stick to terrain with slope angles less than 30 degrees. Being caught in a small or large wet avalanche today may have a consequential outcome. 

    (4/13/2023)

    A handful of D2 wet loose slides released on southerly slopes. This photo is taken from the 2022-23 season. 

    Photo: md

  • Persistent Slabs

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

    Whumpfing collapses, recent avalanches, and shooting cracks are clear signs to stay out of avalanche terrain today. A triggered avalanche will entrain wet snow, which will make it difficult to escape. Slabs may break wider than you expect, and can be triggered remotely. You are more likely to encounter this problem above 6000 feet where more snow exists. The best way to avoid this problem is to give steep terrain a wide berth. 

Avalanche Discussion

Warm, windy, and wet paints a picture of the last 24 hours. Temperatures at 7000 feet climbed to almost 40 degrees Fahrenheit yesterday (Tuesday). Grave Creek Snotell in the northern Whitefish Range tallied up three inches of precipitation, and Flattop Snotell in central Glacier National Park picked up 1.5 inches of precipitation. Unfortunately, this fell in the form of rain. Snowpack heights dropped three to seven inches throughout the forecast area. The Flathead Range and the Swan Range received significantly less precipitation.

Liquid water moving through the snowpack remains the primary concern. Weak layers buried midpack and near the ground may collapse, causing a slab avalanche. We listed Wet Slab in the Whitefish Range due to the amount of rain that fell yesterday (Tuesday). This rain likely caused the entire snowpack to become very wet. The Swan and Flathead Ranges may still have a dry mid pack above roughly 6000 feet, which is why Persistent Slab remains a problem in those ranges.

Avalanches today will likely gouge down and entrain the season's snowpack. Although slides may not be very large, even a small wet avalanche can have a consequental outcome. This is especially true for this time of season where stumps, rocks, and logs are buried just below the surface.

If you plan to go out in the mountains today, I suggest making a plan that does not involve entering avalanche terrain, especially above 6000 feet where the snowpack deepens. This includes walking or riding on flat ground below large avalanche paths. The risk-to-reward ratio simply does not pencil out today.

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