Observation: NWAC Forecaster

All Observations

Basic Information

Observation Date:

November 28, 2022

Submitted:

November 28, 2022

Observer:

NWAC Forecaster - Joe Dellaporta

Zone or Region:

Mt Hood

Location:

Timberline (South aspects from 5800 ft to 6600 ft)

Recent Avalanches?

Yes

Cracking?

Widespread

Collapsing?

Isolated

Small D1 soft slab release above Timberline Parking lot.

Wind rippled snow near Timberline Lodge.

Weather breaks allowed for some viewings of the upper mountain.

Advanced Information

Cloud Cover:

Overcast

Temperature:

18°F

Wind:

Moderate , NW

New/Recent Snowfall:

HST: 45-50 cm

Moderate winds, cold temperatures (staying in the teens Fahrenheit), and limited visibility characterized the morning. Precipitation tapered as the morning progressed. NW winds were productively loading lee aspects throughout the day.

Today we did not have to go far from the Timberline parking lot to find signs of instability. At the trailhead, the temperatures were cold and the winds were productively drifting the new snow around and creating large drifts just within the parking lot. Throughout our tour, we observed multiple shooting cracks and were able to trigger small (D1) soft slabs on test slopes that were 25 cm deep in wind-drifted snow. Seeing these signs of instability kept us traveling on low- angled terrain and avoiding wind loaded areas.

At our transition point at treeline, we observed the strong winds transporting snow onto the lee sides of terrain features and creating cornices along the ridgelines. Windward sides of ridgelines have generally been stripped of any recent snow.

We observed anywhere from 45- 50 cm of new snow on our tour. This new snow was sitting on bare ground in most places we traveled. Many rocks were shallowly buried under this amount of new snow, so this had us skiing very carefully back to the parking lot.

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: 25-30cm Comments: Areas of wind drifted snow were reactive to human triggers. Most likely will find this avalanche problem on the lee sides of ridges and on the upper mountain.

WordPress Lightbox