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Date: 03/07/98br Time: 16:00br Location: Mt. Rose, above Davis Creek (backountry access, not OOB)br Avalanche Size: 2br Elevation: 9,000br Aspect: SE Facebr Incline: 35br Type: Loosebr Water: Wetbr Avalanche Trigger: Skier on convexitybr Sliding Layer: Loose, wet (slush) on pencil hard bed surfacebr Activity: Ski/Boardbr Party Size: 6br People Caught: 1br Partial Burials: 1br Complete Burials: 0br Injured: 0br Fatalities: 0br Transceivers: 457 (all 6)br
Comments: SE face of MT. Rose. 6 (5 ski / 1 board) skied in from Mt. Rose Meadows over the towers under hazy skies.
Rutschblock test indicated 7 (no failure). Descended approximately 1000' while skies cleared and temperature rose over 40 degrees.
During a long traverse under heating surface snow, we observed failures of a 6" to 8" layer comprised of 2" of heavy wet snow on 4" to 6" of two-finger snow atop pencil hard bed surface.
We avoided open slopes and stuck to clearings in trees.
In an unavoidable clearing, one skier descended over a convexity and triggered a loose wet avalanche. In the starting zone, the avalanche was about 15' at the crown, but grew to a width of 60' at the runout from pulling at snow on the flanks.
The skier attempted to ski out of the avalanche but was spun around and fell head first on his back.
The skier managed to flip on his stomach and "swim" on top and toward the slower moving flank snow.
Rather than attempting to kick off his skis, he swam hard for a small group of 6' to 8' pines in the moving snow in the flank.
Skier was able to hook an arm around a small pine and get his head uphill. The skier then continued to pull up the tree until the slide passed by.
The skier was wearing a beacon and all members of the party had beacons and probes. Two of the five remaining skiers/boarders had full vision of the starting zone and the skier during the avalanche.
At worse, the avalanche may have partially buried the skier, however, on a slope of greater size and runout, the potential for a fatal avalanche would have been significant. All in the party were glad that they had stuck to small clearings with relatively no runout and possibility for volume accumulation.
This incident highlighted how quickly (1.25 hours) the sun can change the entire snowpack conditions from safe to hazardous. SE slopes in the Sierra are prone to wet loose and wet slab avalanches in the heat of the day.