Coyote Butte Avalanche

Avalanche Center forecasters and Mount Shasta Ski Park (MSSP) ski patrol investigated a storm slab avalanche just outside the MSSP boundary on Coyote Butte on a 38 deg NE facing slope. The crown was 2 feet deep and 150 feet wide. The avalanche was triggered naturally earlier in the day, estimated around 8:00am; No avalanche beacon signals were detected in the debris, no ski/board tracks were observed entering or exiting. The bed surface of the avalanche was a buried layer of graupel. The graupel layer fell on top of the snowpack on Friday 12/9 with relatively calm wind. Following was the whooper of a storm that brought ~2.5 feet of new snow (1.8" SWE) in a 40-hour period, beginning 2200 hours Friday night.

Avalanche Code: SS-N-R4-D2-I

DATA CODE:

• 1. Date: 20221210
• 2. Time: 0800 (1220 when discovered)
• 3. Observer: Michael Madden
• 4. Path Characteristics:
  • a. Observation Location: Coyote Butte (National Forest Land)
  • b. Aspect: NE
  • c. Slope Angle in Starting Zone: 38
  • d. Elevation: 6850
• 5. Event Characteristics
  • a. Type: SS
  • b. Trigger: N
  • c. Size: D2-R4
  • d. Snow Properties
    • i. Bed Surface: I
    • ii. Weak Layer: 1F, PPgp
    • iii. Slab: PP (DF), F-4F
• e. Dimensions 
  • i. Slab Thickness: 60 cm (24 in)
  • ii. Width: 45 m (148 ft)
  • iii. Vertical Fall: 95 m (313 ft)
  • iv. Length of Run Path: 235 m (775 ft)
• f. Location of Start Zone: T(C). Leeward side of steep convex roll. No anchoring in start zone, run path, or deposition zone.
• g. Terminus: Located in large mature trees half-way between top of Coyote Butte ski lift and base of Gray Butte ski lift.
• h. Total Deposit Dimensions: Not recorded
• i. Avalanche Runout Angle: 24