December 17
Park City ridges, Willow-Beartrap
Elevations, slope angles and aspects
7500-10k+, angles approaching 35°, all aspects
Snow conditions
3-6" of new snow over a variable base, mostly crusted. South facing had a supportable to breakable crust. The effects of Tuesday's southerly winds were noted on other aspects, west facing scoured, other aspects drifted. Wind drifts were both hard and soft, dependent on the amount of shelter from the wind. No observed effect from day time heating. Frequent collapses were felt and heard, from the weakness, both above and below, the pesky rain crust.
Weather
Clear and sunny in the morning with increasing clouds by afternoon. Winds from the south, less than 20 mph. Winds were observed, pluming snow at upper elevations to the south, both Little and Big Cottonwood. Cool temperatures.
Avalanche activity
A third slide was triggered in West Monitor bowl. Initiated by stomping around on the ridge line, perhaps a hundred feet away from the resulting crown. Aspect was ese facing, skier's far left, angle was well over 35°. The slide was 30-40' wide, up to a foot deep and ran about 400 vertical feet. Weak layer was facets above the rain crust. Slide ran on the rain crust, leaving it in place. Very little base under the crust.
Photos
Three slides in West Monitor
Close up of remotely triggered
Several slides were observed in McDonalds, the result of control work, protecting structures in the run out. Aspects were nw to ne facing.
Snow pit
Finally got a look at one of the upper Days fork slides, breaking out below the rock band, well down from the ridge, with newer ski tracks, beside it.
Evaluation
Another few inches of snow following another windy period adds interest and complexity to snow cover. Slides are mostly pockets in areas that have had enough. Shallow snow pack locations have continued recrystalizing under the rain crust with, lower crusts dissolving away. The rain crust along area traveled on PC ridge line is stouter than that observed in Mill Creek and BCC. Slides observed were leaving crust in place, not promoting hopes for future stability. I'd expect a continuation of marginal stability, slides pulling out here and there, some large, others pockety, until an actual storm occurs.
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