Avalanche on Hawk's Peak Tahoe Donner

Location Name: 
Hawk's Peak, North Face and North ridge
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Fri, 12/17/2010 - 15:30
Location Map: 
United States
39° 21' 33.1884" N, 120° 16' 33.6108" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Public
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
28degrees
Trigger type: 
Natural
Crown Height: 
1 ft
Aspect: 
North
Weak Layer: 
Old Snow
Avalanche Width: 
100ft.
Terrain: 
Below Treeline
Elevation: 
7 500ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
500ft.
Number of people caught: 
2
Number of partial burials: 
1
More detailed information about the avalanche: 

I hiked up to Hawk's Peak and dug a pit.  I isolated a column using a pole mounted snow saw.  There was an obvious 1" layer of hoar snow at around 10" deep.  I'm guessing that it was from Thursday night's cold temperatures.  The snow settled when placing a shovel on top of the column.  A small crack/slip appeared when I placed my hand on the shovel.  The hoar snow layer slipped about an inch out of the column on the third wrist tap. 

I skied down an easy ramp on the northwest side of the north facing slope.  Upon reaching halfway down, at about 6800' I noticed a debris field.  It wasn't immediately clear where this avalanche debris came from.   I thought, 'this is a very recent naturally occurring avalanche, time to get out of here.'  But I was curious as to where it started.  There's a north-south ridge that leads back up Hawk's Peak with a distinct cornice from westerly winds.  I skinned up parrallel to the ridge, keeping my distance and sticking to low-angle slopes.  A short way up I could make out where the soft snow had slid off the cornice and down the hill.  I would classify it as a class 2 avalanche.  Small but slid more than 50 meters.

I should have hightailed it on out of there but I thought I would take a low angle across over to the northeast side of Hawk's Peak.  On the way up I saw where another avalanche occurred right off the top of Hawk's Peak, about 50-60' wide, 1' crown and slid 50 meters.  I angled up a little trying to stay within tree cover and keeping a watchful eye uphill.  Sure enough, down came another one.  I could see it coming through the trees.  I took three steps back to get behind a 10' tree.  Unfortunately I couldn't get right up next to the tree.  Fortunately it was light sluff.  I was pushed about 10' down hill eventually coming to a stop with the avalanche debris just above my knee.  This one was wider than the other two and made it's way through the trees pretty easily.  I took my skins off and skied off the north facing slope. 

It was a big mistake to have not gotten out of this area as soon as I saw the first natural avalanche or perhaps even on the pit evaluation.

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: 
Static
Wind Direction: 
West
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Light snow on the way up.  Very little wind but some.  I skinned up without glasses which were fogged but I skied down with googles.