Avalanche

Cascadilla

FACFlathead Range & Glacier NP
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Quick report

We traveled to Cascadilla in the Middle Fork to look closely at a very large D3 hard slab avalanche on Nyack Mountain.

  • This slide occurred Thursday, March 2, during an intense wind storm with gale-force winds resulting in substantial wind loading.
  • The trigger was a wind slab avalanche that released 200 feet below the ridgeline. 
  • Crown depth was estimated at 5+ feet deep. The width of the slide is approximately 1500 feet, estimated using CalTopo.
Numerous natural loose dry sluffs occurred during the recent stormy weather. These were harmless size D1. We observed triggered sluffs from skiers on steep terrain and from prolonged solar input. These were also D1 in size.

Weather

Air Temp
22
Cloud Cover
broken
Wind Loading
light
Rain Elevation
1000'
Recent Snowfall
12
Snow Avail For Transport
large amounts

Prolonged periods of the sun with light winds and cool ambient air temperatures.

Avalanche

Size
D3 R4
Type
HS
Aspect
NE
Trigger
N
Elevation
7150 ft