Manto nivoso

Flattop Mountain

Mark DundasFlathead Range & Glacier NP
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Quick report

Cracking
specific

We ventured to the Continental Divide to see if the wind had been at work.

  • Large swaths of wind-affected terrain had been stripped of snow by prevailing westerly winds.  
  • Fields of older, thick, hard slabs were observed in many leeward locations. In some places, these rested on a layer of weak faceted snow on the ground (see image). 
  • Fresh, soft slabs formed overnight were reactive to the weight of our skis, but cracking did not extend beyond our skis. 
  • The snowpack is shallow in sheltered and exposed locations, limiting travel.
  • One previously reported slab avalanche was observed in extreme terrain on Little Dog Mountain (see image).
Cracking beneath our skis in recently formed soft wind slabs. Cracks did not propagate beyond our skis.

Weather

Air Temp
25
Cloud Cover
broken
Wind Loading
none
Rain Elevation
4000
Recent Snowfall
5
Snow Avail For Transport
small smounts

The morning sun gave way to overcast skies mid-day. The wind was non-existent in this typically windy location.

Snowpack

The snowpack depth varied between 0 to 36 inches. The higher-end totals were in wind-drifted locations. Snowpit tests required hard force to break through the overlying slab to achieve failure in faceted weak snow surrounding crusts. No propagation was observed.