Storm slabs and ice bridge over the moat
Location Name: Forecaster Observation - Marion Lake, Flathead Range Observation date: Monday, February 4, 2019 - 17:00 |
Is this an Avalanche Observation: Yes |
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Observation made by: Forecaster
Location
Tabs
Avalanche Details:
Date and Time of Avalanche:
Monday, February 4, 2019 - 11:00
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
Within storm snow
Trigger:
skier
Trigger Modifier:
Intentionally Triggered
Destructive Size:
D1 Relatively harmless to people.
Relative Size:
R1 Very Small
Crown Height:
Less than 1 ft
Avalanche Length (Vertical Run):
100ft.
Avalanche Width (Average width):
30ft.
Avalanche Location:
Soft slabs breaking about 2" to 4" deep, but entraining down to the 2/2 MFcr, all aspects and observed at mid/low elevations. Given the unusually reactive and widely propagating behavior, I suspect the failure layer has some small grained faceting (melt-layer recrystallization?), but my hands were too cold to dork out with a lens.