Public Observation #2021-501

Submitted:
December 17, 2021 7:11 PM
Observation Date:
December 17, 2021
Zone or Region:
Central Cascades
Activity:
- Select -
Location:
Vista Butte
Did you trigger any avalanches? 
Yes
Was it intentional? 
Yes
Avalanche Type:
Cornice Break
Size:
D1: Relatively harmless to people
Elevation:
Aspect:
E
Comments:
Small 2'-4' cornice released above E facing slopes after jumping above them with skis 2-4x. Top 2" of corniced sheared separately, Q1, possibly due to underlying surface hoar layer from a couple days prior? (Surface hoar layer was noted elsewhere in Central Oregon region). The rest of the cornice broke off in cracks & chunks, Q3.
Did you see shooting cracks? 
Yes
Did you experience collapsing or whumpfing? 
No
At the summit of Vista Butte: Signs of wind scouring including 1"-2" wind texture on snow surface at top of E facing slopes. Denser wind load layer 2"-4" thick with cracks underfoot propagating up to 2ft. 2'-4' cornices on E facing slopes released after jumping 2' behind them on skis 2-4x. Top 2" of corniced sheared separately, Q1, possibly due to underlying surface hoar layer from a couple days prior? (Surface hoar layer was noted elsewhere in Central Oregon region). The rest of the cornice broke off in cracks & chunks, Q3. Mild/thin layer of surface hoar noted throughout Vista Butte area in the morning after a clear/cold night. Some of it was rounding in the sunshine, but it will probably remain as most of the day was cloudy/cold and the area is mostly shaded from sunlight - will likely be buried under tonight's/tomorrow's snowfall.