Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
NH-S
Observation Date:
January 9, 2021
Submitted:
January 9, 2021
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
Blewett

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Elevation:
NTL
Aspect:
N
Comments:
Multiple old, now snow-covered SS-N-R2-D2 or 3 on various aspects of E, N, NW in NTL band or on steep rollovers BTL. The storm cycle winding down 4/5/6 January 2021 overwhelmed the weak snowpack across the Wenatchee Mountains.

Signs of Unstable Snow

Did you see shooting cracks? 
No
Did you experience collapsing or whumpfing? 
Yes, Isolated

Observations

Calm and Clear turning Obscured with light east winds as valley fog rose to 6000'+ by noon. Surface hoar BTL and NTL. Wind not enough to transport snow NTL at 1200. 12/9, 12/22 crusts with weak snow and 1/3-1/4 density changes easily identified in pit at 5800' N. No tests conducted.

Media

Profile 5800' N

Advanced Observations

Observed Avalanche Problem #1: 
Wind Slab
Comments: 
25cm from snow surface, the density change in the storm is reactive under foot and easily identified in pits. Where wind has packed snow into a cohesive slab this layer is the source of collapses while traveling NTL.
Observed Avalanche Problem #2: 
Persistent Slab
Comments: 
HS 120-150cm, with bottom 15-25cm fist hard depth hoar/facets. Local collapses BTL in areas with 90cm of snow or more, five days after the storm passed.
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