Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
David Grampa
Observation Date:
December 19, 2021
Submitted:
December 21, 2021
Zone or Region:
West South
Activity:
Skiing/Snowboarding
Location:
Crystal

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
No
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
6900ft
Aspect:
NE
Comments:
Small storm slab avalanche triggered in Powder Bowl at previous day's interface. Six inch crown extended between Gazex avalanche control systems.

Signs of Unstable Snow

Did you see shooting cracks? 
Yes, Isolated
Did you experience collapsing or whumpfing? 
Yes, Isolated

Observations

Avalanche control systems had triggered avalanche in the adjacent chute but failed to trigger an avalanche in this chute. This was an inbounds at Crystal. Slab avalanche was considered highly unlikely as the slope was directly below the Gazex avalanche control systems. Loose avalanche was expected. However, a small slab avalanche propagated in the chute at the previous day's interface. Suspect the interface was created by the rapid warming event accompanied by rain on Saturday followed by rapid cooling that occurred Saturday night accompanied by high winds and 6 to 8 inches of new snow.

Media

Public Field Report: Crystal
Public Field Report: Crystal
Public Field Report: Crystal

Advanced Observations

Observed Avalanche Problem #1: 

Comments: 
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