Forecaster Avalanche Observation - Hash Mountain/Lost Johnny, Swan Range

Location Name: 
Forecaster Avalanche Observation - Hash Mountain/Lost Johnny, Swan Range
Region: 
Swan Range - East Side (Hungry Horse Reservoir access)
Date and time of avalanche (best estimate if unknown): 
Wed, 01/20/2016 - 11:00
Location Map: 


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

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
35degrees
Trigger type: 
Skier
Crown Height: 
1 ft
Aspect: 
North
Weak Layer: 
Within storm snow
Avalanche Width: 
200ft.
Terrain: 
Below Treeline
Elevation: 
6 700ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
100ft.
Number of similar avalanches: 
2
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

From the safety of a flat ridge, we were able to easily trigger three wind slabs on small slopes without stepping onto the slope. They all occurred on northerly aspects between 6700 and 7100 feet

#1:Depth = 12-14 inchesWidth = 75 feetVertical Fall = 200 feet

#2:Depth = 12-14 inchesWidth = 125 feetVertical Fall = 300 feet

#3:Depth = 12-14 inchesWidth = 200 feetVertical Fall = 400 feet 

We also observed a small natural slab avalanche at about 5200 feet adjacent to the Lost Johnny trail/road. With objective avalanche hazard high above this slab we did not want to investigate. It occcurred low down in the first large avalanche path on the west side of the trail/road before the road's end. It appeared to be about 50-60 feet wide and 1.5-2 feet deep. The bed surface layer is unknown. It ran about 200 feet. (see image).

Avalanche Photos: 
Avalanche observation video: 

January 20, 2016 - Wind Slabs and Storm Slabs, Hash Mt./Lost Johnny, Swan Range

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate (Small trees sway)
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: 

Snowfall in the morning was around 1 inch/hour. It then tapered by 1:00 pm. Winds were out of the southwest at 5-15 mph with gusts to 25 mph.

Activity: 
Snowmobiling