Avalanche activity and Continued wind loading in the Sherwins

Mammoth rock
Submission Info
Wednesday, December 25, 2019 - 12:30pm
Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Snowpit Observations
More detailed information about the snowpack: 

Toured up to Sherwin ridge above Mammoth rock this morning to get a look at how the moderate winds are affecting leeward slopes. Increased Wind speeds have affected snow in exposed areas at lower elevations, and significant wind loading was observed along the ridgeline. Along our ascent, we stopped to look at the poop chute. I observed a small pocket of 4” sensitive wind slab at the entrance that ran more like a loose dry avalanche after I kicked it loose.  Significant wind transport was occurring along the ridge, and the moderate winds were ideal for building wind slabs. Many signs of instability were noted. We observed several size 1 wind slab avalanches with crown heights ranging from 4inches to 2ft between Mammoth rock bowl and the hose. With several new tracks in the area, the cause of each release was hard to tell, but my investigations suggest both natural and skier triggered slabs. In addition to the avalanche activity, we observed fresh cornice growth and cracking (both along the cornice lines, and under our skis). We opted to descend via the Main Avy path and were careful to avoid the obviously wind-loaded entrance.   Upside down Wind board and other textured snow was observed far lower on the slope, then we expected though we were happy to find nice low-density storm snow for the majority of our descent.  Below 9000’ or so travel became more challenging because of the multitude of trees and bushes choking the lower slope.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

Mostly clear skies, moderate SW winds, and cold temperatures made for a lovely Christmas day in the mountains.

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