Date of Observation: 01/21/2016
Name: Zach Guy
Aspect: East, South East
Elevation: 11,000 ft. Near Treeline
Avalanches: Our deepest condolences go out to all of those involved or affected by this incident. Below are preliminary avalanche details from a site visit shortly after the incident. Full accident investigation and report to follow. At approximately 13:45, two people riding “Canadian” on a snowmobile unintentionally triggered a large soft slab avalanche that failed in old snow layers. SS-AMu-R3-D2-O. One of the riders was buried in a tree well. Members of the group responded and extracted the victim. Irwin Guides responded shortly after and evacuated the victim while performing CPR. The crown was 95 cm thick on average, 500 feet wide and ran 140 vertical feet. The slab failed on a layer of rounded facets above a thin melt-freeze crust (Jan 14th crust). See profiles. The slope was an ESE to SE aspect near treeline at 11,000 feet. Above the burial location, the crown pulled back to 32 degrees, and the slope was as steep as 42 degrees along this vertical transect.
Weather:
Snowpack:
Crown Profile above the burial location
Crown profile, near right flank of avalanche
Looking uphill from near the burial location
Avalanche outline and Google Earth overview