The Mt. Shasta Avalanche Center says a wet-slab avalanche occurred one-fourth of a mile below the Bunny Flat Trailhead Monday afternoon. Avalanche Forecaster Ryan Sorenson with the Shasta-Trinity Forest Service said no one was near the avalanche when it happened. It was discovered around 3:30 pm reports Action News Now.
Sorenson said the R3D3 avalanche was caused by water trickling through melting snow. The water pooled and lubricated a bed surface made of clustered rounded melt forms three millimeters thick with a thin ice crust. The slab consisted of wet rounded grains F-4F hard. The bottom inch (2-3 cm) was saturated with water. Dryer rounded snow was found under the bed surface 4F-1F hard. The avalanche ran on a south southeast aspect (154°). The crown ran 500 feet along the slope and averaged 19 inches thick (50 cm). The debris pile filled up one lane of the road 8 feet deep.
Sorenson says the avalanche is classified as D3, which could potentially bury or damage a car, break a few trees, or injure or kill a person. He says the temperatures have been steadily rising over the last week. High temperatures for the last three days recorded at Sand Flat 6,750 feet are 50, 50 and 53 degrees F. Low temperatures have stayed just below freezing for the last three nights. Little wind has been recorded over the last three days.
The Center says wet weather above 6,000-foot snow levels will return Tuesday night. A few inches of snow is expected. Researchers say they feel this is an isolated event. Similar events would be confined to the road going to Bunny Flat where there are small, steep unsupported slopes created by snow removal operations.