A long runner
Location Name: Forecaster Observation - Flathead Range Observation date: Monday, January 17, 2022 - 15:45 |
Is this an Avalanche Observation: Yes |
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Observation made by: Forecaster
Location
Tabs
Avalanche Details:
Date and Time of Avalanche:
Friday, January 7, 2022 - 14:00
Number of avalanches:
1
Avalanche Type:
Hard Slab
Failure Plane/Weak Layer:
Other - explain below
Trigger:
natural
Start Zone Slope Angle:
40
Aspect:
Northeast
Starting Elevation:
7400'
Destructive Size:
D3.5
Relative Size:
R4 Large
Crown Height:
4 ft
Avalanche Length (Vertical Run):
3000ft.
Avalanche Width (Average width):
500ft.
Avalanche Location:
Date and Time of Avalanche:
Friday, January 7, 2022 - 14:00
Number of avalanches:
1
Avalanche Type:
Hard Slab
Failure Plane/Weak Layer:
Other - explain below
More information or comments about the avalanche:
This slide appears to have failed on the December 3 crust/facet layer.
Trigger:
natural
Start Zone Slope Angle:
40
Aspect:
Northeast
Starting Elevation:
7000'
Destructive Size:
D3 - Could destroy a car, a wood house, or snap trees
Relative Size:
R4 Large
Crown Height:
5 ft
Avalanche Location:
Date and Time of Avalanche:
Friday, January 7, 2022 - 14:00
Number of avalanches:
10
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
Within storm snow
More information or comments about the avalanche:
These appear to have failed during the January 7 Atmospheric River. The aspects varied from NW-N-NE.
Trigger:
natural
Start Zone Slope Angle:
35
Aspect:
North
Starting Elevation:
above-treeline
Destructive Size:
D2 Could bury, injure, or kill a person.
Relative Size:
R2 Small
Crown Height:
1 ft
Avalanche Length (Vertical Run):
500ft.
Avalanche Width (Average width):
100ft.
Avalanche Location:
Date and Time of Avalanche:
Wednesday, January 12, 2022 - 12:00
Number of avalanches:
10
Avalanche Type:
Wet Loose
Failure Plane/Weak Layer:
Within storm snow
More information or comments about the avalanche:
These appeared to be triggered during the rain event on January 12. Aspects ranged from NW-N-NE.
Trigger:
natural
Start Zone Slope Angle:
40
Aspect:
North
Starting Elevation:
above-treeline
Destructive Size:
D2 Could bury, injure, or kill a person.
Relative Size:
R2 Small
Avalanche Length (Vertical Run):
400ft.
Avalanche Width (Average width):
50ft.
Avalanche Location:
The debris seems to be associated with the January 7 Atmospheric River. This slide started just beneath the ridgeline and may have been triggered by a cornice fall, but I could not identify this for sure. The avalanche appears to have failed on the December 3 facet/crust combination.