Valanga

Anderson/Prairie Creek

Jon PreussGalena Summit & Eastern Mtns
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Foto dell’osservazione 1

Quick report

Collapsing
widespread

We remotely triggered two avalanches from adjacent non-avalanche terrain. Both slides failed on the 12/13 facet layer beneath a crust. At 9,300 feet in exposed westerly terrain, the winds were strong, transporting significant amounts of snow in wind-exposed areas.

Weather

Cloud Cover
obscured
Wind Loading
moderate
Rain Elevation
None!
Recent Snowfall
17 cm
Snow Avail For Transport
large amounts

It snowed S2-3 for most of the morning. We left around 1200 and there was 17 cm on the Nordic track.

Snowpack

I dug on an east-facing slope at 9,400 feet and observed a PST 20/100 (END) result on the 12/13 layer, located 73 cm down. However, I was unable to get this layer to propagate in Extended Column Tests (ECTs). In contrast, storm interfaces at 20 cm and 25 cm depths propagated in ECTs with 2 and 5 hits, respectively, and these results were repeatable. I couldn't identify the 12/21 crust at this location, though it hasn't appeared to be a significant factor in stability for the areas I've traveled recently. After completing the pit, I collapsed the weak layer while getting into my skis, remotely triggering a small slide in the steeper terrain below me.

Avalanche

Size
D2
Type
SS
Count
2
Aspect
NW
Trigger
AS
Elevation
8610 ft

While traversing across lower-angle terrain above the slope, we remotely triggered an avalanche below us. The primary failure occurred on the 12/13 facets, with evidence of an additional failure at a storm interface, possibly from 12/27.