Natural persistent slabs above Skiumah Lake
Location Name: Forecaster Observation - Skiumah Lake, Flathead Range Observation date: Thursday, December 20, 2018 - 16:15 |
Is this an Avalanche Observation: Yes |
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Observation made by: Forecaster
Location
Tabs
Avalanche Details:
Date and Time of Avalanche:
Wednesday, December 19, 2018 - 02:00
Avalanche Type:
Hard Slab
Failure Plane/Weak Layer:
Old snow
Trigger:
natural
Aspect:
North
Starting Elevation:
7000
Destructive Size:
D2.5
Relative Size:
R2 Small
Crown Height:
4 ft
Avalanche Length (Vertical Run):
500ft.
Avalanche Width (Average width):
250ft.
Avalanche Location:
Date and Time of Avalanche:
Wednesday, December 19, 2018 - 02:45
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
Unknown
More information or comments about the avalanche:
Viewed from debris pile; crown appeared to be a storm / wind slab but ran a far distance and entrained wet snow lower down.
Trigger:
natural
Aspect:
North
Starting Elevation:
6700
Destructive Size:
D2.5
Relative Size:
R3 Medium
Crown Height:
2 ft
Avalanche Length (Vertical Run):
2100ft.
Avalanche Width (Average width):
300ft.
Avalanche Location:
Date and Time of Avalanche:
Wednesday, December 19, 2018 - 02:45
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
New/old snow interface
More information or comments about the avalanche:
Trigger:
natural
Aspect:
North
Starting Elevation:
above-treeline
Destructive Size:
D1.5
Relative Size:
R1 Very Small
Crown Height:
1 ft
Avalanche Location:
2 persistent slab avalanches broke just above the 11/3 crust. One may have been triggered by a step down wind slab