Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Nate Hough-Snee, Chris Cox
Observation Date:
March 1, 2023
Submitted:
March 1, 2023
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
Icicle Creek

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Hard Slab
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
7800'
Aspect:
E
Comments:
We saw a large, natural wind/hard slab with crown to 4-5 meters (estimated across valley) on the flanks of Cashmere Mountain. We couldn't see the runout, just the crown and debris was spun in. 50-55 degree terrain below a cliff band. HS-N-R3-D2

Signs of Unstable Snow

Did you see shooting cracks? 
Yes, Isolated
Did you experience collapsing or whumpfing? 
Yes, Isolated

Observations

We went for a walk to 7500' to see how the snowpack was skiing and to view surrounding alpine terrain ahead of the storm. A calm, clear day gave way to moderate to strong winds and obscured sky by afternoon. S1 showers pushed in from the west by late afternoon and transport ramped from moderate to intense by our exit time. T'was definitely a transitional weather day with the late winter sun having an effect early alongside the increasing winds late. We observed multiple avalanche problems (wind slab, dry loose, wet loose, and a single large hard slab) from the last 3-4 days, traveling primarily on relatively steep northeasterly and easterly aspects.

The snowpack structure is still suspect over the Valentine's crust in hand pits to 6200' where it's 25-30cm deep. Above 6200', the crust is thinner and eventually goes away by 7000' although facets exist at the same interface in the pack (40+cm at 7000'). Hand shears were resistant on sheltered terrain although we managed a few small collapses and cracks in wind-affected terrain.

It seems like the incoming wind and snow may start to build a slab over the Valentine's crust-facet layer (25-35cm down) in the east central. Right now, sheltered areas haven't really developed the slab structure that we've seen elsewhere in the more wind-affected portions of the zone.

Media

WL-N-R1-D1 at 5400' S/SE
Moderate to strong winds and moderate to intense transport viewed in the core Enchantments
HS-N-R3-D2 on Cashmere Mountain around 7600' E
A mid-slope wind slab avalanche on a convex rollover as viewed across valley. SS-N-R1-D1.5 NE 7000'
Moderate to strong winds and moderate to intense transport viewed on Cashmere Mountain
SS-Ny-R1-D1.5 A large crown from a wind slab triggered by a loose snow avalanche sometime recently 5600' NE

Advanced Observations

Observed Avalanche Problem #1: 
Wet Loose
Comments: 
WL-N-R1-D1 at 5400' S/SE Valentine's crust as interface
Observed Avalanche Problem #2: 
Dry Loose
Comments: 
DL-N-R1-D1 Multiple dry loose on steep 45-60-degree features. In one case, a tree bomb triggered a dry loose that stepped down to a wind slab around 5700'. Cornice drops also resulted in long dry loose releases from ridgelines.
Observed Avalanche Problem #3: 
Wind Slab
Comments: 
SS-Ny-R1-D1.5 A large (40 meters wide) continuous crown wrapped around multiple convex rollovers and was triggered from above by dry loose and tree bombs. Runout less than 35 meters. Multiple small avalanche crowns (3-5 meters wide) visible nearby on steep rolls in 45-degree slopes. Likely from 26-27 Feb wind and snow events.
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