West Face Gray Butte Avalanche

Gray Butte - West Face - Sparse trees near treeline, 7,800 feet, 38 degrees: An intentional ski cut along the convexity of this avalanche path resulted in a good size slide around 2:30pm. The crown was ~2-2.5 feet deep, 60 feet wide and ran ~500 feet into denser forest. Nobody was caught. A brief period of graupel fell on top of the snowpack Friday December 9th, just before the weekend storm. Approximately 2-2.5 feet of fresh snow fell on top of this graupel layer over a 40-hour between Saturday December 10 to Sunday December 11. The slab failed on this weak layer of graupel. This is the same layer where the avalanche on Coyote Butte yesterday morning failed, 12.10.22.

Avalanche Code: SS-ASc-R3-D2-I

DATA CODE: 

• 1. Date: 12.11.2022
• 2. Time: 1430 hours
• 3. Observer: Meyers/Madden
• 4. Path Characteristics: Trees
  • a. Observation Location: Crown of slide path
  • b. Aspect: West
  • c. Slope Angle in Starting Zone: 38°
  • d. Elevation: 7,800 feet
• 5. Event Characteristics
  • a. Type: Soft Slab Avalanche (SS)
  • b. Trigger: ASc, Skier (ski cut)
  • c. Size: D2/R3
  • d. Snow Properties
    • i. Bed Surface: Old storm snow (I)
    • ii. Weak Layer: Graupel (PPgp)
    • iii. Slab: New storm snow (PP, DF)
• e. Dimensions
  • i. Slab Thickness: 2-2.5 feet
  • ii. Width: 60 feet
  • iii. Vertical Fall: ~300 feet
• f. Location of Start Zone: Near treeline, ~7,800 feet
• g. Terminus: Dispersed among large trees
• h. Total Deposit Dimensions: Not measured
• i. Avalanche Runout Angle: Not measured