Large scale natural avalanche observed on Janine's Peak

Location Name: 
Janine's or Jeannine's Peak
Region: 
Desolation Wilderness Area (including Emerald Bay)
Date and time of avalanche (best estimate if unknown): 
Thu, 03/17/2011 - 01:00
Location Map: 
United States
38° 54' 26.2296" N, 120° 7' 46.6896" 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,
Trigger type: 
Natural
Aspect: 
Northeast
Weak Layer: 
Other
Avalanche Width: 
1 000ft.
Terrain: 
Above Treeline
Elevation: 
9 200ft.
Bed Surface: 
Other - explain below
Avalanche Length: 
300ft.
More detailed information about the avalanche: 

We skied up Eagle Creek to gain the Eagle/Maggie's/Velma ridge this morning 3-17-11 and arrived with a view of the Janine's or Jeannine's Peak and Kalmia Bowl area around 11 AM.  We observed not the occurrence but the existing crown of this rather large avalanche (see photo) which may have happened in the early morning hours.  If it had happened much before that, the clarity of the crown might have been much more obscured by the constant wind loading that appeared to be occurring over the top of Janine's Ridge with high and continuous south to west winds.

The crown appears pretty big -- when I zoom in there are enough known rocks and trees for comparison, I'm estimating 5 feet at the highest points, though an average closer to 3 or just under 3 feet.  No way to know for sure since we were two miles away.  The really impressive and scary thing about this one is how wide it was.

This was nearly the only natural (or avalanche of any kind) we observed despite gaining a very widespread view of the entire area from the tops of both of Maggie's Peaks.  The other one was a smaller (about 100' x 100' x 12") one on the open granite slabs of Eagle Lake Buttress, not much of a surprise at all, east facing.

Needless to say we did not set foot anywhere near the Janine's Ridge area and considered carefully whether to even ski any north-northeast aspects at all today.  Our eventual northside runs on Maggie's South and Maggie's North showed very small amounts of cracking but no settling or whumping, and no slab activity despite lots of cutting -- even though we observed a very well defined density change about a foot down.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Wind Speed: 
Strong
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Clear day.  You guys know better than we do what the weather was out there last night or early this morning when this natural probably occurred.  The storm had cleared but strong wind transport likely did not stop all night or all through today.  Very strong south to west winds were observed all the way down Cascade Creek Canyon.  We initially planned to lunch at Azure Lake and it was literally too windy even down in its bowl to stay there, so we dropped all the way down to Snow Lake and even then had to take shelter in trees to relax and eat.