Lawinenlagebericht

Bitterroot

West Central Montana Avalanche Center
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Lawinengefahr

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

Kernpunkte

6 to 12 inches of new snow and strong shifting winds over the last 24 hours created dangerous avalanche conditions. Skiers and riders are likely to trigger fresh wind slabs at middle and upper elevations today. Smooth pillows of snow that may be stiff and hollow sounding indicate the presence of windslab. Shooting cracks and recent avalanches are clear signs of instability. Avoid wind-loaded slopes over 35 degrees. 

Lawinenprobleme

  • Wind Slabs

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

    Skiers and riders are likely to trigger fresh wind slabs at middle and upper elevations today. Over the last 24 hours, 6 to 12 inches of new snow combined with strong shifting winds built fresh wind slabs on all aspects. Yesterday there were several natural and skier-triggered wind slabs reported throughout the forecast area. Strong winds initially blew out of the east, then shifted to the west yesterday afternoon. Due to the shifting winds, wind slabs could be found on all aspects and in atypical locations. However, east aspects are the most suspect today. 

    Wind slabs are often found just below ridges and in cross-loaded gullies, but you could also trigger them well below ridges today. Cornices, wind lips, and drifts indicate wind direction and loading. Stay alert for smooth pillows of stiff or hollow-sounding snow, which indicate the presence of wind slab. Shooting cracks and recent avalanches are clear signs of instability. Avoid wind-loaded slopes over 35º.

Avalanche Discussion

After a week of relatively stable conditions primarily dealing with small loose avalanches, yesterday’s storm changed the game. Today, dangerous avalanche conditions exist due to sensitive fresh wind slabs. 

The storm brought showery snowfall and strong shifting winds. Snow totals are variable within each zone, but the winds were strong enough to build thick wind slabs even in areas that received less snow. In the Southern Bitterroot yesterday, wind slabs were 12 inches thick after only 3 inches of snow fell. They will be thicker today. In the Seeley Lake zone near Morrell Mtn, a foot of snow had fallen by the end of the day, and a natural wind slab left 9 feet of debris on the Morrell Mtn road. 

The snow fell on a mix of slick crusts and weak old snow surfaces. These will make the wind slabs more sensitive. Avalanches could run farther than normal on the slick crusts. Today is a good day to take a step back and give the wind slabs time to heal. We should be back to more stable conditions soon. 

In areas that received the deepest snow totals, you could find reactive storm slabs today on slopes sheltered from the wind. Stay alert for signs of instability like shooting cracks or recent avalanches. Remember, even a small avalanche into a terrain trap like a gully, roadcut, or bench could bury you. 

It should be a nice weekend with calmer winds, warmer temperatures, and some sun forecast for Sunday afternoon. When the sun comes out to play, look out for wet loose avalanches in the new snow in addition to wind slabs. If the snow is wet and rollerballs start, it's a sign to move to lower angle slopes or shadier aspects. 

Please let us know what you find out there today by submitting an observation. 

Ski and ride safe.

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