February 21
Yellow Jacket-Alexander Basin
Elevations, slope angles and aspects
6400-9200', angles over 35°, north east and west facing.
Snow conditions
Storm total in the area at 9k was around 2 feet.
There was a density change 8" or so down, easily felt with ski pole and trail breaking.
There was a lot of natural sluffing on that layering.
Ski cuts yielded little in the way of sluffing and no fractures.
Cornice drops did produce some surface sluffing.
Some sun exposed did warm enough to crust with cooling, dependent on cloud cover.
Weather
Mostly cloudy skies, moderate temperatures. Wind were light down off the ridges.
Avalanche activity
Natural slides were observed in Davis Gulch on the face of Gobblers
the Raymond slabs
and Wilson chutes, northwest facing into Alexander Basin.
I went for a closer look at that one.
The slide initiated with sluffing off the rocks, fracturing on the old snow surface.
Walking up the bed surface suggested the old surface was the pesky January 16th rain crust, exposed by the windy period prior to the storm.
The fracture was up to four feet deep. At that location, I found the rain crust removed with the slide running on faceted snow below.
Rain crust was several inches thick. Looking at several other spots, found it to be quite variable in thickness.
Evaluation
Settlement significantly improved stability.
Views of natural activity suggest shallow new snow slides may go to the old surface which, may or not, include rain crust and faceted snow.
Potential is dependent on older snow layering and may well be isolated but, wouldn't wanna get caught in one of those.
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