Echo Peak dry slab

Location Name: 
Lower bench below Echo Peak
Region: 
Echo Summit Area
Date and time of avalanche (best estimate if unknown): 
Thu, 02/23/2017 - 13:00
Location Map: 
United States
38° 51' 11.4552" N, 120° 4' 5.1132" W
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Public
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
40degrees
Trigger type: 
Snowboarder
Crown Height: 
1 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
100ft.
Terrain: 
Above Treeline
Elevation: 
8 000ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
400ft.
Number of similar avalanches: 
2
More detailed information about the avalanche: 

During my ascent of the lower portion of Echo Peak I observed a recent avalanche on the upper reaches of the main bowl. From what I could tell a snowboarder had traversed riders-right (southeast) down the ridge from true Echo Peak dropping down towards a smaller bowl. As the rider approached the entrance to the bowl on about the fifth turn the rider triggered the slide which propagated the entire width of that bowl (~100') and ran it's entire length (~400'). It looked like the rider stayed on the top edge of the slide path and was able to ride out to the right to a ridge for safety. The weak layer looked to be the transition from wet to cold dry snow late in the recent storm cycle. This must have been a close call as there were cliff bands and a narrowing choke in the bowl below the rider. If anyone witnessed first hand please submit.

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Calm
Precipitation: 
None
Air temperature trend: 
Static