Leavitt Cirque

Location Name: 
Leavitt Cirque
Region: 
BWRA
Date and time of avalanche (best estimate if unknown): 
Thu, 03/29/2018 - 14:12
Location Map: 


Red Flags: 
Rapid warming
Obvious avalanche path

Observation made by: Avalanche Specialist
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
49degrees
Trigger type: 
Other - explain below
Crown Height: 
6 ft
Aspect: 
Northeast
Weak Layer: 
Old Snow
Avalanche Width: 
125ft.
Terrain: 
Above Treeline
Elevation: 
10 666ft.
Bed Surface: 
Old Snow
Avalanche Length: 
800ft.
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
Did the avalanche hit a building, vehicle, or structure?: 
No
More detailed information about the avalanche: 

This avalanche looks like a combination of problems occuring in succession. This feature above Leavitt Lake frequently forms a large cornice & below that a deep wind slab commonly lingers. It can be surmised that rapid heating caused the cornice to creep itself until gravity overcame the shear strength of the snow collection, causing it to break & fall. This mass of snow fell onto an already Deep wind slab, overloading the slab & propagating a fracture amidst the rocks. This R2-D3 naturally triggered avalanche could destroy a building & definitely kill a group of riders underneath it. Only a few feet adjacent there is a 13' crown from a deep slab avalanche which released with the last storm. We will continue to keep cornice produced avalanches within our hazard summary. 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
None
More detailed information about the weather: 

A warm afternoon, topping out around 40F at 10K. Clouds were increasing towards 15:00 and the snow was firming up. Evidence of R&R & melting of the snow surface.