Skiumah storm slabs and shooting cracks
Location Name: Forecaster Observation - Skiumah Lake, Flathead Range Observation date: Monday, January 21, 2019 - 15:15 |
Is this an Avalanche Observation: Yes |
---|
Observation made by: Forecaster
Location
Tabs
Avalanche Details:
Date and Time of Avalanche:
Sunday, January 20, 2019 - 20:15
Avalanche Type:
Hard Slab
Failure Plane/Weak Layer:
Old snow
Trigger:
natural
Start Zone Slope Angle:
35
Aspect:
North
Starting Elevation:
above-treeline
Destructive Size:
D2.5
Relative Size:
R3 Medium
Crown Height:
3 ft
Avalanche Length (Vertical Run):
1200ft.
Avalanche Width (Average width):
250ft.
Avalanche Location:
Date and Time of Avalanche:
Sunday, January 20, 2019 - 07:45
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
New/old snow interface
More information or comments about the avalanche:
Storm slabs appeared to have failed at different times during the past 4 days of stormy weather.
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:
This slide was triggered by a storm slab on the evening of the 19th or morning of the 20th. Appears to be a Persistent Slab which we assume failed on a buried weak layer and/or crust from December. The debris field had the appearance of soft slab characteristics without the large blocks typically associated with hard slab debris.