Snowpack

Observation: Powder Mountain Backcountry

Greg GagneOgden
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Quick report

Red Flags
Recent Avalanches, Wind Loading, Cracking, Collapsing, Poor Snowpack Structure
Red Flags Comment
<p>Numerous collapses observed throughout the day, failing on the layer of faceted snow that was preserved prior to the 11/29 storm.</p>

Photo and video of NE aspect at 8,500 with ECTP5

In areas without a stronger slab on top of the buried facets, pit scores were ECTN (no propagation). This correlates with other field observations in the Ogden and Salt Lake mountains where you need a stronger/denser slab on top of the buried facets to produce avalanches. My biggest concern is areas that were wind-loaded during the Wednesday/Thursday wind event or later this weekend where the strong wind slab on top of facets has the structure to produce large avalanches. Video below explains this further.

Snowpack

Instability Comment
<p>The November PWL layer is now buried about 50-60 cms deep, although in areas with wind-loading, over a meter deep. Numerous collapses today and several poor pit scores with full propagation &lt; 10 taps. </p> <p>Southwest winds were creating pockets of fresh wind drifts along exposed ridgelines. With increasing winds Sunday and Monday, fresh wind drifts are likely.</p>

Friday's storm snow settled out to 15-20 cms (6-8") on top of the 50 cms (18-20") that fell earlier this week.

 

HS 8,500' - 9,500' is about a meter +/- 20 cms. Although in wind-loaded terrain, the snowpack is closer to 1.5 meters deep.