Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Renee Shapiro
Observation Date:
April 9, 2021
Submitted:
April 12, 2021
Zone or Region:
Snoqualmie Pass
Activity:
Skiing/Snowboarding
Location:
North Slopes- Chair Peak

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Dry Loose (Sluff)
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
4100
Aspect:
N
Comments:
North Slopes of Chair Peak, D2
Slab failed on 4/7 interface
65 cm deep crown, some propagation, runout all the way to Snow Lake
Photo:

Signs of Unstable Snow

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

Observations

Route: Travel plan was to explore Wright Peak via Cache Couloir. Approach began at Snow Lake TH and we climbed up the Thumbtack on Chair. After digging multiple hand pits, we opted to ski the Cache Couloir after seeing graupel on top of the 4/7 interface and lots of wind affect on the North slopes of Chair Peak.
Snowpack: 8-12 inches of new, low density snow in past 24 hours on top of 4/7 interface
Weather: Vert few clouds, direct solar radiation starting at 0800. Calm winds. Clouds thickened to broken coverage around 1300
Crown Profile: Graupel at 4/7 interface, CT 20 Sudden Planer- Q1

Media

Graupel at 4/7 interface. Transition to faucets on S slopes, transition to rounds on N slopes
Crown profile on D2 avalanche on North Slopes
Wet loose on South slopes of Chair
Crown Profile

Advanced Observations

Observed Avalanche Problem #1: 
Wet Loose
Comments: 
All south facing aspects had small loose wet activity
Observed Avalanche Problem #2: 
Wind Slab
Comments: 
Lots of wind, scoured slopes, textured snow
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