Skier Triggered Avalanche on Mt. Lincoln

Location Name: 
Mt. Lincoln
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Thu, 01/28/2010 - 11:30
Location Map: 
United States
39° 16' 54.5952" N, 120° 20' 3.7248" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
38degrees
Trigger type: 
Skier
Crown Height: 
1 ft
Aspect: 
Northwest
Weak Layer: 
Storm Snow
Avalanche Width: 
350ft.
Terrain: 
Above Treeline
Elevation: 
7 400ft.
Bed Surface: 
Old Snow
Avalanche Length: 
700ft.
Number of people caught: 
2
Number of partial burials: 
1
More detailed information about the avalanche: 

Avalanche investigation findings differ significantly from initial report in regards to aspect, slab characteristics, and weak layer.

Skier triggered avalanche that occurred on Jan 28. Avalanche occurred just above treeline on a convex portion of the slope in complex terrain. Crown wraped N-NW-W aspects. Crown height ranged from 10 to 30 cm in most areas with isolated sections up to 60 cm. Weak layer was lower density snow below higher density storm snow slab. Rain crust likely aided in propagation. No faceted crystals were observed at the crust. The snow up to 2 cm above the crust was well bonded to the crust. Surface melt freeze crust formed overnight after the avalanche occurred.

Photo 1: Crown and debris of avalanche.

Photo 2: West side of Mt. Lincoln showing the greater terrain of where the avalanche occurred. Avalanche is not visible in this photo, but occurred just above treeline in the far lower drainage.

Snowpit or crown profile photo or graph: 
Avalanche Photos: 
Avalanche observation video: 

20100129 Mt. Lincoln 001.MOV

Weather Observations
Air temperature: 
Precipitation: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: