Wind/Hard Slab on Flatiron

Location Name: 
Flatiron Summit
Region: 
Purcell Mountains
Date and time of avalanche (best estimate if unknown): 
Mon, 02/22/2021 - 11:30


Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Terrain Trap

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
36degrees
Trigger type: 
Skier
Crown Height: 
2 ft
Weak Layer: 
Other - explain below
Avalanche Width: 
150ft.
Terrain: 
Near Treeline
Elevation: 
5 800ft.
Bed Surface: 
Old Snow
Avalanche Length: 
100ft.
More detailed information about the avalanche: 

Flatiron Mountain in the Purcells, 5800' elevation, North aspect, 36 degree (estimated) slope on convexity, 2021/02/22 11:30am, remote trigger by skier, wind packed 2' depth hard slab released on surface hoar layer above January rain crust. HS-ASr-R3-D1.5-O

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour