Wet-loose -Castle Lake

Today’s observation comes from Castle Lake at 6,200 feet between the hours of 1000 and 0100. With spring knocking on the front door, our goal was to investigate the sensitivity of northeast facing cornices and the wet loose avalanche problem near and below treeline.

Today, human triggered wet-loose slides on steep northeast facing terrain were inevitable. If you were on steep terrain, it would want to slide. Small amounts of moving snow off test slopes would gouge deeper and encapsulate as much snow as possible as it moved downhill. A sizable D 1.5 slide was intentionally triggered and was big enough to bury, seriously injure, or kill someone if caught. The SUV sized cornices overhanging north and east ridgelines displayed settlement cracks multiple feet behind their edges. Fresh cornice debris was seen below countless ridgelines. The sound of water dripping could be heard while standing on top of ridges. On south aspects little to no wet loose activity was observed. The snow displayed more resistance to sliding on southerly slopes than northerly. A moderate wind was blowing from a northwest direction with a clear sky and above freezing temperatures. 

• Observation Location: Castle Lake 
• Elevation: 6,200 feet
• Date: 2023.04.10
• Time: 1200
• Observer: E.Falconer S.Clairmont 
• Sky Conditions: [Clear (CLR) | Few (FEW) 
• Current Precipitation: Type - NO
• Air Temperature: 50 °F
• Surface Penetration: Ski penetration (PS) = 12 in ([15cm), boot penetration (PF) = 20 in (50 cm)
• Wind Direction: NW
• Wind Speed:  Light (L), 1-16 mi/hr, twigs in motion | Moderate (M), 17-25 mi/hr, small trees sway