Upper Cement Creek

Holy apocalyptic wind event!  The recent northerly wind event produced significant wind slab and persistent slab activity in the land of large fetches and shallow snowpack.  The features of concern (pencil hard slabs up to several feet thick) are easy to recognize and avoid, but they continue to produce shooting cracks today under sled.  Winds weren't working with just the recent few inches of snow, but in some fetches, the entire winter's snowpack.   Alpine terrain was raked and eroded by winds, down to the ground in places.  The sastrugi offered safe options for moving through steep terrain; the snowpack was semi-supportive and much softer under sled in the wind-rippled snow, in contrast to zero ski pen on the wind slabs.  Below treeline, there are no apparent avalanche concerns other than facet sluffing; snowpack is shallow and unsupportive under sled.  

 I investigated the crowns of two persistent slabs on SW and SSE aspects ATL. The avalanches failed 2 to 3 feet deep on the 11/30 interface, under pencil-hard drifted slabs, with fairly strong mid-slab crusts from the mid-December warmup (the 12/23 crust was 2-3cm thick, pencil to knife hard).  I looked at two other wind slab crowns on SE aspects N/ATL and the slabs failed on weak facets at the start of the most recent storm (~1.5mm facets, F hard, often with a thin soft crust in the vicinity).