Tahoe National Forest Sierra Avalanche Center

Pit dug in open below treeline terrain to look at Dec 11 PWL. Inconsistent ECT results on Dec 11 PWL. Collapses have become increasingly localized over the past 5 to 6 days.

Snowpit dug in below treeline terrain to look at the Dec 11 persistent weak layer.

Steve Reynaud dug this pit. Andy Anderson recorded it.

Snowpit dug just off ridge in wind protected terrain

Pit dug in near treeline terrain to assess Dec 11 PWL.

Test pit dug in near treeline terrain to look at Dec 11 PWL.

Pit dug on open shaded slope below treeline. PST @ 35 cm had SF into upper facet layer that then propagated to column end. Freezing rain event created crust on top of old near surface facets which are still weak. This looks like a developing PWL to be named the Dec 11 facet layer.

A weak and shallow snowpack exists in this elevation band along the Sierra Crest. The faceting process has accelerated over the last week or so with multiple areas now showing unsupportable conditions.

Artificially loaded 10cm PST 28/100 SF at 46cm in near surface facet layer.