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Semi supportable, Fully edgeable
Location Name:
Swan River State Forest
Observation date:
Thursday, January 20, 2022 - 14:30
Is this an Avalanche Observation:
Yes
Observation made by:
Public
Tabs
Quick Observation
Field work produced the best possible results:
High quality dust on crust at mid elevations
2-4 inches of snow on top of the crust
Crust was semi supportable (Under the tree canopy was firmer from drippings)
Crust was 3 inches thick at 5000' decreasing to 0.5 inches at 6500'
Wind was strong from the SW but blowing snow was light-moderate
While descending a wind exposed ridge we tested fresh wind slab and found them to be thin but sensitive.
Raining below 4800' on descent at 15:00
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Swan Range - South (south of Swan Lake)
Activity:
Skiing
Snowmobiling
Snowshoeing
Snowpack Details
Snowpack and Weather Details:
Terrain
Elevation of observation:
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation:
N
NE
SW
W
NW
Red Flags:
Avalanches from the past 2 days
Rain on snow
Blowing snow
New Snow in the past 24 hours:
4.00in.
More comments about the snowpack and weather:
Dug around in new snow above the crust. Couldn't positively ID any surface hoar. Where cohesive the new snow appears to be sliding on preserved low density stellar/dendrites. Crust was 4F hard and 6 cm thick at 5000' decreasing to 2cm (and friable) at 6500' N aspect.
Blowing Snow:
Light
Wind Speed:
Strong (Whole trees in motion)
Wind Direction:
Southwest
Sky Cover:
Obscured by fog, etc (X)
Highest Precipitation Rate:
Very Light Snowfall (S-1)
Avalanche Details
Avalanche Details:
Date and Time of Avalanche:
Thursday, January 20, 2022 - 14:30
Number of avalanches:
1
Avalanche Type:
Soft Slab
Failure Plane/Weak Layer:
New/old snow interface
Trigger
Trigger:
skier
Trigger Modifier:
Intentionally Triggered
Terrain
Start Zone Slope Angle:
35
Aspect:
North
Starting Elevation:
near-treeline
Size
Destructive Size:
D1 Relatively harmless to people.
Relative Size:
R1 Very Small
Crown Height:
Less than 1 ft
Avalanche Length (Vertical Run):
50ft.
Avalanche Width (Average width):
20ft.
