Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
April 11, 2022
Submitted:
April 11, 2022
Observer:
NWAC Forecaster - Andrew Kiefer
Zone or Region:
Mt Hood
Location:
Mitchell Creek/MHM (All aspects, 4600-6500ft)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Widespread
Collapsing? 
None Experienced

Media/Attachments

Mitchell Creek Profile
Shovel-tilt tests produced easy, sudden failures within storm snow ↓10cm and ↓30cm. (Mitchell Creek, NE aspect, 5600ft)
Skin tracks refilled quickly with ongoing snowfall and wind loading
Shallow slab avalanche within new snow. Unknown trigger. (NE aspect, 5400ft)

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
15-20°F
Wind:
Moderate , NW
New/Recent Snowfall:
80cm (32in) HST since 4/8

Blizzard conditions with snowfall rates of 1-2in per hour. Poor visibility with blowing snow extending below treeline.

Several small artificially-triggered avalanches with loose dry and soft slab characteristics. Avalanches ran within the top 30cm or less of HST. No natural avalanches observed and all artificially triggered avalanches were smaller than D2.

Snowpack Observations

80cm (32in) of right-side-up (F-4F-1F) storm snow was well bonded the the 4/8 crust (P). Snowpack tests resulted in sudden planar fractures on two inter-storm layers ↓10cm and ↓30cm. These were the same interfaces where recent avalanches failed. Surface slabs were very soft and cohesionless in wind-sheltered areas. Evidence of wind-loading did extend below treeline with fresh wind lips and small cornice formations. Observations above treeline were limited. Ski penetration was around 30cm while boot penetrations was 80cm. No concerning test results on the 4/8 crust.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Storm Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 4/8