Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Josh Hirshberg
Observation Date:
March 16, 2021
Submitted:
March 16, 2021
Zone or Region:
Stevens Pass
Activity:
Skiing/Snowboarding
Location:
Henry Creek

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Wet Loose
Size:
Size 1: Relatively harmless to people
Elevation:
5600
Aspect:
E
Comments:
We watched a small (D1.5 )avalanche release in extreme terrain around 12:30p. It ran approximately 600ft through cliffs and slopes >45 degrees. It may have been caused by a small cornice fall.

Other activity- More evidence of the widespread avalanche cycles in late February. We saw crowns on ESE, 5,600ft from avalanches that ran 1,600ft in Henry Creek to size D3.5. The debris contained multiple small and mature trees. In Whitepine Creek we observed 3-4 debris piles of size D3.5-4. These originated on SSE aspects of Jim Hil and ran around 2800ft. I suspect there are more avalanches on the south side of Jim Hill that I couldn't see. These avalanches all likely ran during the cycles of either Feb 22nd or 26th and many if not all of them likely involved the mid-January weak layer.

Signs of Unstable Snow

None reported

Observations

Weather- Calm w an occasional light gust at 6,400ft. Strong sun, FEW thin clouds.

Snowpack- Surfaces varied from surface hoar (2mm) and surface facets (0.5-1.0mm) on N above 6,000ft to decomposed stellars on shaded, N aspects below 5,000ft, to melt forms on most other slopes. 5cm of recent snow from 3/15 formed very small drifts up to 10cm deep near and above treeline. These were very isolated, though still touchy on shaded northerly aspects. At 5,700ft, N height of snow was >350cm. we found planar, but rough shears down 35cm below older wind drifted slabs. The mid-January crust was down 240cm.

Media

A crown on E, 5,600ft, Henry Creek. This avalanche ran during the avalanche cycles of late February, likely on the mid-January weak layer
A crown on ESE, 5,550ft, Henry Creek. This avalanche ran during the avalanche cycles of late February, likely on the mid-January weak layer. This avalanche ran 1,600ft to size D3.5
Avalanche debris in Henry Creek from late February containing many trees.
Avalanche debris in Whitepine Creek, on the south side of Jim Hill from late February.
Weak snow found near the surface at 6,200ft, N on Jim Hill. Surface hoar (2mm) and near surface facets (0.5-1.0mm).
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