Snowpack Tests at the Bottom of the Sherwins

Submission Info
Saturday, March 17, 2018 - 12:00pm
Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
37° 37' 1.2684" N, 118° 59' 42.6984" W
Snowpit Observations
More detailed information about the snowpack: 

Sierra Mountain Guides avalanche course toured up to the Mill City area under the Sherwins mid-day to observe wind slabs, storm slabs, and persistent weak layers in the snowpack. Moderate SW winds were effectively loading NE aspects just below the Sherwin ridge for most of the day. Snow transport was mostly through turbulent suspension and saltation. It was hard to see from our vantage point and the blowing snow, but it appeared that there may have been recent natural avalanches (D1) on the looker's right side of Mammoth Rock Bowl and also looker's right of the Hose, just below the cornices.

Kick tests on Panorama Dome produced an R1, D1 wind slab avalanche on a ENE facing 45 degree convexity at about 8400'. Kick tests along the road cuts near Mill City had no results.

Snowpack tests just below the Log Cabin Mine site near Mammoth Rock showed that the rain event last week wetted the snowpack up to at least 8500' and the basal facets in our snow profiles had been moistened, were rounding, and produced only one unrepeatable CTH SC 80cm down. All other snowpack tests near the mine were inconclusive: CTE BRK down 11cm in the recent storm snow, CTM BRK down 36cm in the recent storm snow, ECTX. HS in this location was 115cm. Over on Panorama Dome the group dug in a leeward drift where HS was 192cm. CTE SC down 30cm in 0.5mm 4F hard facets under wind deposited rounds, CTM, ECTN22, and RB4 MB in the same layer. There was plenty of grauppel mixed into the top 4cm of recent storm snow. HST in the 8500-9000' elevation band was ~50cm.

Skies today were few clouds, below freezing temps, light to moderate SW winds below 9000', but moderate to intense at 10,000' on the Sherwin Ridge with consistent blowing snow (moderate to intense) until approximately 230pm.

Snowpack photos: 
Blowing Snow on the Sherwins
Weather Observations
Blowing Snow: 
Air temperature: 
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 
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