Mammoth Rock Trees

Submission Info
Tuesday, April 17, 2018 - 3:30am
Red Flags: 
Snowpit Observations
More detailed information about the snowpack: 

Observer: d lewis
Loc: Mammoth Rock Trees
Lat/Lon:37.6129, -118.9923
Elevation: 9300 f
Aspect: NE Angle: 35°
Signs of Instability: Shooting Cracks, Wind Loading
Sky Cover: OVC
Precipitation: Snow, Light snowfall - 1 cm/hour
Wind Speed: Moderate Beaufort
Wind Direction: SW
Current Temp:-5 to -10°C Trend:
Blowing Snow: Light
New Snow 24-Hours:20cm Storm:20cm 
Boot Penetration: 25cm
Snow Stability: Good
Stability on similar slopes:Good
Avalanche Danger: Moderate

Comments: Toured up into the Sherwins to assess the new snow stability. The snow at Mammoth Rock trailhead (~8300’) is getting quite thin. ~6” on the road and 3” was new. As you move up toward the base Mammoth Rock (~8450’) snow cover begins to improve.  A very solid & dry melt/freeze crust, 25 to 35 cm thick, under 15 to 30cm of new snow. The new snow has yet to fully bond to the old snow surface, prone to sluffing on steep terrain. Moderate SW winds with strong gusts throughout the day. Noted light wind loading on NE aspects below 10,000’ along ridgelines and in channeled terrain. The new snow showed slight slab like characteristics in the top 5 to 10 cm but too soft to propagate. Kick turn tests showed the snow easily sliding off the firm snow below but no tendency to propagate beyond what is disturbed. Minor cracking noted in treewells with ski cuts. Small Wind Slabs forming below the crest of the Sherwins with cracking extending 2 meters (~6’). Test slopes yielded a single D1, small Wind Slab formed in a shallow depression, NE aspect, ~9300’, ~38 degrees.  ~20’x 20’x 20 cm. 


Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

WX – Snow showers all day, some intense (>2cm/1” hour). Graupel (3mm) and rimed precipitation particles. Occasional strong SW winds with some crossloading noted in channeled terrain below 10,000’. 

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