Negro Canyon Observations

Location Name: 
Negro Canyon
Region: 
Donner Summit Area
Date and time of observation: 
Thu, 01/21/2010 - 11:30
Location Map: 
United States
39° 20' 43.296" N, 120° 17' 38.76" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Toured into the East Fork of Negro Canyon.   New storm snow from the week is at 95cm at this location.  Large cornices are built out and very tender today, several released naturally sometime during the night/early morning along the ridge.  I was able to kick some cornices off that were small car size, most entrained some snow and went downhill, some had small propagation associated  with them.  Getting a slab to propagate today was much harder than I had thought.  The deeper weaknesses in the storm snow have gained more strength and I had no results on the old snow/storm snow interface with CT's or ECT's.  The propagation with the cornice drops and the skier triggered slab propagation I had today was consistently early in last nights storm snow about 1-1 1/2' thick slab.   

Photo#1: Small skier triggered slab on a small test slope

Photo#2:  Natural cornice failure sometime during the storm, many areas on this ridgeline had large cornice blocks that fell downslope.

Photo#3:  Shooting cracks off ski tips to small slab while testing slope. 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

ECTN

Any other comments about the observation or links to outside pages that have more info on the observation: 

 

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Air temperature trend: 
Static
Wind Direction: 
Northeast
Accumulation rate: 
More detailed information about the weather: