Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Andrew Kiefer
Observation Date:
December 18, 2020
Submitted:
December 18, 2020
Zone or Region:
West North
Activity:
Skiing/Snowboarding
Location:
Heather Meadows/Swift Creek

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
4300-5000ft
Aspect:
N
Comments:
A handful of shallow natural and skier-triggered avalanches failed within the most recent storm/wind-drifted snow today.
Photo:

Signs of Unstable Snow

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

Observations

Avalanche hazard increased throughout the day with additional snow and strong southerly winds. Over 40in/100cm of recent storm snow sits atop a firm crust (12/9). Interstorm layers down 6in/15cm and 12in/30cm are the primary culprits in recent avalanche activity over the past 24hrs, which has mostly been small (D1) although poor visibility limited observations. Snowpack tests produced resistant planar fractures and no propagation. The recent storm snow appears uniform with a favorable hardness profile (F-1F). Below the 12/9 crust, the snowpack is consolidated and strong. Continuous snow begins around 2500ft with a significant increase in the height of snow near 4000ft.

Media

Shallow skier triggered avalanche (D1) on a north aspect at 5000ft
Natural avalanche (D1) within wind drifted snow on an east aspect at 4300ft
A shovel tilt test produced resistant planar fractures with easy force on interstorm layers down 15cm and 30cm

Advanced Observations

Observed Avalanche Problem #1: 

Comments: 
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