Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Dallas Glass
Observation Date:
February 14, 2021
Submitted:
February 14, 2021
Zone or Region:
West South
Activity:
Skiing/Snowboarding
Location:
Miriam Creek/Gunsight Bowl: White Pass

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
6300
Aspect:
NE
Comments:
Gunsight chutes: A small cornice triggered a sizable soft slab avalanche that appeared to run on the 2/11 interface. The slide traveled quickly and reached the main bench below the bow. NE 6300', 45-60cm deep, 75' wide. SS-ACi-D2-R2-O.
Photo:

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
6300
Aspect:
NE
Comments:
Noted three slab avalanches from 2/13. These slides were ~10" (25cm) deep but some looked up to 2' (60cm).
Photo:

Signs of Unstable Snow

None reported

Observations

Terrain: Very short tour today in the Miriam and Gunsight areas.

Snowpack: 2-3" (5-7cm) of new snow over a thin rime crust. ~18-25" (45-55cm) of recent storm snow over the 2/11 interface. Upper snowpack is generally right-side-up and progresses from Fist to 4 Finger to 1 finger to pencil with each storm. The 2/11 interface appears to contain small facets and faceted stellars. Snowpack tests showed sudden results suggesting a failure could propagate and produce an avalanche.

The Mid-January crust was down about 5' but I did not test it today.

Weather: Noticeably warmer. Increasing snowfall during the day. Light winds with no blowing snow.

Media

Snow profile from Gunsight Bowl
Tilt-test from profile sight highlighting the 2/11 interface
Natural crowns in Gunsight chutes from 2/13
Crown of triggered avalanche from 2/14 in Gunsight Chutes
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