Observation: NWAC Forecaster

All Observations

Basic Information

Observation Date:

March 20, 2022

Submitted:

March 20, 2022

Observer:

NWAC Forecaster - Andrew Kiefer

Zone or Region:

Mt Hood

Location:

Sand Canyon (5000-6500ft, E-S-W aspects)

Recent Avalanches?

Yes

Cracking?

Isolated

Collapsing?

None Experienced

Skier triggered cornice and a very small shallow wind slab

Skier trigger cornice and small shallow wind slab

Ski triggered cornices and small shallow wind slabs

Cornices along the east facing aspect of Sand Canyon

Wind textured surfaces near and above treeline

Advanced Information

Cloud Cover:

Overcast

Temperature:

20-25°F

Wind:

Moderate , W

New/Recent Snowfall:

6-8in (15-20cm) HST since 3/17

Brief clearings early with views of the upper mountain. Obscured skies for most of the day. Moderate westerly winds.

Avalanche Observation Comments:

Triggered several cornices and two shallow wind slabs (D1) on small tests slopes. No evidence of natural avalanche activity on the upper mountain.

15-20cm of wind-affected storm snow (F-4F) was fairly well bonded to a thick melt-freeze crust (K) buried 3/17. Tests targeting the 3/17 interface produced resistant planar fractures and no propagation. Below 3/17, the snowpack is consolidated, strong, and spring-like with alternating layers of melt-freeze crusts and rounded grains several of which were moist. The past week of storms and wind overbuilt cornices which were large and sensitive to triggers. Wind slabs were 10-40cm thick and stubborn to triggers. Exposed west-facing ridges were scoured to the 3/17 crust and south and east aspects were fat and loaded. Despite the wind affected surfaces from the 3/19 wind event, ski quality was good with smooth and fast turns in the cold snow.

Problem	Location	Distribution	Sensitivity	Size	Comments
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: 3/17

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