Detailed Accident Report

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Date: 2008-12-25
Submitted By: WWAN
Place: Poulsenís Gully-Squaw Valley Ski Area
State: CA
Country: USA
Fatalities: 1
Summary: 1 Skier caught, buried, and killed

***OFFICIAL REPORT***

On the morning of Thursday December 25th, a 21 year old skier was killed in an avalanche near Poulsenís Gully in the Squaw Valley ski area. The avalanche occurred in bounds in an open area. The soft slab avalanche ran approximately 350 vertical feet through old growth trees into an open gully. The avalanche was approximately 25 meters wide with an average crown height of 40 cm. (SS-AS-R2D2-S). The avalanche was unobserved and the skier likely died from apparent trauma. The ski patrol had done avalanche control work with explosives on the slope prior to the accident.

Weather and Snowpack:

On December 24th, the National Weather Service issued a Winter Storm Warning for Christmas eve through Christmas day in the Lake Tahoe area. Over 2 feet of snow was forecasted to fall with strong winds creating blizzard conditions. At Squaw Valley, over 2 feet of snow fell in a 24 hour period. Wind gusts on the ridges reached 132mph, and steady wind speeds of over 50mph were recorded through Christmas morning.

The first significant snow for the season in the Poulsenís gully area fell on December 13th. Steady snow fell from that time through the 25th. Ridgeline wind gusts on the 19th, reached 141mph, as a result, much of the snow in Poulsenís Gully was stripped during that major wind event . About 3 feet of snow fell in the Poulsenís gully area between the 19th and the 24th. Moderate winds, skier compaction and avalanche control compacted and consolidated that snow into 1F hardness. Avalanche control was performed in the Poulsenís gully area on 19th and the 22nd with successful results. As the Christmas storm began on the 24th, a light density layer of snow fell before the precipitation intensity, temperature, and wind increased creating a density inversion.

The ski patrol performed avalanche control on the morning of the 25th, on Snow King mountain (Poulsenís gully) and the adjacent mountain, KT22. Avalanche control measures yielded good results, releasing many class 2 avalanches. The average crown size was 2 feet, releasing on the density inversion on the new snow interface. Avalanches were widespread and many of them ran full path. KT22 closed on the 25th for avalanche danger.

The Sierra Avalanche Center issued an advisory for the 25th. Rating the danger as CONSIDERABLE near and above treeline on slopes steeper than 35 degrees on N-NE-E aspects with pockets of CONSIDERABLE on NW and SE aspects. Below treeline on open slopes steeper than 35 degrees, the avalanche danger was MODERATE with pockets of CONSIDERABLE on the NW-N-NE-SE ASPECTS. Human triggered avalanches were forecast to be probable.

ACCIDENT AND RECOVERY

The Red Dog chairlift opened 10:00am. The victim rode the first chair and with the reporting witness. The avalanche likely occurred within the first few minutes that the chairlift was open to the public. At 11:15, the witness reported the victim missing to the ski patrol. The ski patrol returned to the area where the last seen point was with the witness, 9 patrollers, 3 dogs, and 2 Recco detectors. It was known that the victim was not wearing an avalanche transceiver and was wearing a Recco reflector on his pants. A ski and goggles were found on the surface matching the victims. At 12:59, the victim was located completely buried under 85cm of snow using an avalanche rescue dog and a Recco detector. The rescue dog and the Recco detector located the victim at approximately the same time. The victim had suffered massive head trauma.

THE AVALANCHE

The avalanche was classified as SS-AS-R2D2-S. The slope was 40 degrees near the crown at an elevation of 7,350 feet. The average depth of the crown was 40cm and the avalanche was approximately 25m wide. The avalanche ran 350 vertical feet through old growth trees and came to rest on a bench. The debris had an average depth of 4 feet, with as much as 8 feet deposited in front of trees.