Professional Observation - Going-to-the-Sun Road Avalanche Program, GNP

Location Name: 
Professional Observation - Going-to-the-Sun Road Avalanche Program, GNP
Region: 
Outside of the Advisory Area
Date and time of avalanche (best estimate if unknown): 
Wed, 04/06/2016 - 17:00
Location Map: 


Red Flags: 
Recent avalanche activity
Rapid warming

Observation made by: Professional Observer
Avalanche Observations
Avalanche Type: 
Wet
Trigger type: 
Natural
Crown Height: 
10 ft
Aspect: 
North
Weak Layer: 
Other - explain below
Avalanche Width: 
80ft.
Terrain: 
Above Treeline
Elevation: 
7 600ft.
Bed Surface: 
Ground
Avalanche Length: 
300ft.
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: 

Along the Going-to-the-Sun Road today, we observed a fair amount of recent avalanche activity.

1. Glide Avalanche. A glide avalanche occurred along the east ridge of Heavens Peak some time after 2:00 pm on 4/6/2016 and before 8:00 am on 4/7/2016. This occurred on a NE aspect around 7400 feet.

2. Wet, loose avalanches up to size D1.5 occurred on numerous aspects. This natural activity began around noon on east/southeast aspects today (4/7/2016).

3. An interesting glide avalanche/soft slab avalanche. The repeat offender glide avalanche referred to as the Heavens Peak Remnant Glacier path (does not affect the road) releases every year. This year it appeared to fail some time before the small 4/5/2016 storm as there was new snow on the bed surface (smooth rock slabs). However, a very large (1500-1800 ft. wide) soft slab released within the same path as well. Based on the amount of new snow that filled in both crowns, it appears they both released at or around the same time. One possbility is that the glide avalanche released naturally and triggered the soft slab or vice versa. It appears as if the soft slab released on a deeper weak layer in the snowpack, but not the ground. It is difficult ot determine, but we estimate the glide avalanche crown depth at around 10-12 feet and the soft slab around 4-6 feet deep.

 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Calm (No air motion)
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
None
More detailed information about the weather: 

Clear, warm day with temperaturs warming into the mid-40s at 7500 feet by 4:00 pm.