February 14
Area:
Box Elder from Alpine
Elevations, slope angles and aspects:
6300’-10000’, angles to 38°, north, northeast, east and west aspects.
Avalanche activity:
West pass on Box Elder.
The avalanche ran at the end of the storm. 300’ wide mostly east facing but wrapped around to north facing. 2’ or so deep +and -. It only ran about 200 vertical because the slope flattens quickly. Weak layer was well developed facets. Total snow was around 50” with 30” faceted under the last two storms. The lower layering in the crown was pencil and the upper was one finger.
East facing upper Box Elder. There were two debris piles in the lower apron. I could see a partial crown of one from the top of the north chutes. The ne face may also have ran. The slides ran about 2000’ vertical. There was also evidence of avalanche in the nw cirque and the north facing.
I also spotted a crown on the west face in the north facing portion of the big gully.
I triggered an avalanche in the skiers left chute, north chutes on Box Elder. Started in the right chute, finding a foot or less over the old bed surface. Ski cut all the way across both chutes. Ski cut back across still finding only about a foot of snow. Started a slow ski down pole probing. I could see the choke in the chute down lower and wanted to avoid it so I began traversing towards the west ridge. The slide broke above me, with cracking and collapsing around my skis.
I punched it towards the ridge wedging myself in a group of trees, while the slide continued breaking out and heading downhill. I had debris around my feet but didn’t get any impact. That slide was 50’-60’ wide, up to about 30” deep. Most of it ran as a repeater, with faceted snow over the old bed surface from the January slide. A portion and what I think initiated the slide was on well developed faceted snow outside the parameters of the previous slide.
On my approach up the ridge,
I could still see the 8’ crown from the previous slide and could also see that it had about 2’ of snow loaded on top in that corner.
Snow Surface and conditions:
There was a skiff of snow at about 6500’, increasing in depth to about 8’-10" at 10’000’. West facing had a solid sun crust, east facing was a marginal to breakable crust. I experienced only localized collapsing while ascending the north ridge in drifted areas. Pole probing indicated stronger mid pack layering over the faceted snow with another faceted layer above the mid pack under the new. Instability showers added perhaps and inch later in the day.
Weather:
Partly cloudy with increasing clouds and winds, gusting to about 20mph prior to and during the instability showers. Mild temperatures.
Evaluation:
Most of the available avalanche paths ran at the end of the last storm. These were pockety and not full width or depth. As I discovered, those that did not run and have wind load, primarily east and northeast facing still have potential.
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