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Wet-loose -Castle Lake

Location Name: 
Castle Lake
Castle Lake
Date and time of observation: 
Mon, 04/10/2023 - 12:05pm
Observation made by: 
Red Flags:
Recent avalanche activity
Rapid warming

Location Map

96067 Mount Shasta , CA
United States
41° 13' 8.0076" N, 122° 22' 46.2288" W
California US

Snowpack Observations


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 



  • Debris pile from wet-loose slide near treeline on northeast aspect
  • Intentionally triggered slide. Northeast aspect near treeline.
  • Debris pile
  • Settlement cracks multiple feet behind this cornice
  • Drooping overhung cornices on northeast ridgeline
  • Snowpack structure on south aspect 6,200 feet
  • Snowpack structure on north aspect 6,200 feet
  • Pinwheels: snow wanting to gather together is evidence of wet surface conditions
  • Middle Peak. tones of point releases and wet loose activity
  • Left Peak. Signs of old wind slab crown. Wet snow surface
  • Mount Shasta capped by lenticular clouds

Weather Observations


Cloud Cover: 
75% of the sky covered by clouds
Blowing Snow: 
Accumulation rate: 
Air temperature: 
Above Freezing
Air temperature trend: 
Wind Speed: 
Wind Direction: