Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
January 1, 2023
Submitted:
January 1, 2023
Observer:
NWAC Forecaster - Irene Henninger, Hilary Groh, Kris Stemmler
Zone or Region:
West North
Location:
Cowap Peak (All aspects, 2500ft-5500ft)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

Sunny SE aspects in the foreground had a crust under a thin dry surface layer. Areas that stayed in the shade didn't moisten and no crust formed.
D1.5 Wet Loose Avalanche which ran early afternoon on a SW aspect at 4800ft.
A pit at 5500ft, N, on Cowap Peak yielded no extended column test result
Rollerballs which ran midday as the surface layers moistened. SE, 5300ft
Old large glide cracks from the rain event near Christmas covered by about 2ft of new snow.. E, 5300'.
The cloud bank approaching at 1300hrs, which persisted in the area for 2hrs, blocking intense early afternoon sun.
NW facing cornice near Cowap Peak, 5500' and wind lips indicating recent subtle wind-effect.. Weather was calm while we were there.

Advanced Information

Weather Summary

Wind:
Calm

Mainly clear, but low-level clouds obscured skies 1300-1500. Intense long wave losses kept surfaces cool (aside from brief obscured period) on all aspects.

Snowpack Observations

40-60cm of new snow are over the Xmas crust 5000-5500ft, and total snow heights averaged 1.5-2.5m at those elevations. At 3000ft about 2ft of snow was present, which is approximately where the snowline for the post Xmas snowstorms began accumulating.

In the several pits we dug we found that the previous few days' weaknesses within the new snow layers above the Xmas crust had strengthened, although we were not on notably wind loaded areas to test them.

Intense solar input moistened southerly slopes ~20cm deep midday. A subsequent thin crust formed as the sun's direct angle left the slope. Rollerballs occurred. We saw one natural D1.5 wet loose avalanche on a steep SW slope. We triggered one wet/dry loose D1 in the afternoon in a steep, tree-covered gully area that had about 15cm of new snow over Xmas crust, running down the gully on the crust interface. Approx 4500ft.

Impressive old glide cracks/avalanches were identified on the SE slopes of Cowap Peak, likely from Xmas warming. Now covered by ~2ft of snow. It was difficult to determine what they were at first. Photos didn't do justice.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wet Loose
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
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