Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Zack Wentz
Observation Date:
February 25, 2021
Submitted:
February 25, 2021
Zone or Region:
Snoqualmie Pass
Activity:
Skiing/Snowboarding
Location:
Alpental Valley - Big Trees

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
No
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
4200’
Aspect:
NE
Comments:
Location: In opening skiers right of Big Trees. Depth: 15cms on new graupel interface Width: 50 feet Length: 150 feet

Signs of Unstable Snow

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

Observations

Avalanche Obs: See above. Numerous sz 1 storm slabs on steep E facing features skinning up to Source Lake.

Snowpack Obs: Numerous hand shears resulted in uneven breaks but easy failures within the new storm snow (graupel). Upper 15cms consists of settled storm snow and graupel and is 4F- in hardness in most sheltered locations.

Weather Obs: Consistent graupel at S2 all day. Surface form: approx. 3mm graupel. AM wind was calm up to Source Lake and Pineapple Basin; PM wind was M from the E, with L blowing snow at ridge top starting around 2pm.

Overall a great day to be out! The graupel is skiing really well!

Advanced Observations

Observed Avalanche Problem #1: 
Storm Slab
Comments: 
Location: Up to Pineapple Basin & top of Big Trees. Widespread, especially above Source Lake
Potential Size: Up to D2 in the right terrain feature. We only observed D1s.
Likelihood of Triggering: Likely
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