Observer: d lewisLoc: Mammoth Rock TreesLat/Lon:37.6129, -118.9923Elevation: 9300 fAspect: NE Angle: 35°Signs of Instability: Shooting Cracks, Wind LoadingSky Cover: OVCPrecipitation: Snow, Light snowfall - 1 cm/hourWind Speed: Moderate BeaufortWind Direction: SWCurrent Temp:-5 to -10°C Trend:➘Blowing Snow: LightNew Snow 24-Hours:20cm Storm:20cm Boot Penetration: 25cmSnow Stability: GoodStability on similar slopes:GoodAvalanche 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.
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’.