Avalanche

Blewett Pass- Rock Slide to Naneum

Matt Primomo and Lee LazzaraEast Slopes Central
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Observation photo 1Observation photo 2Observation photo 3

Quick report

Collapsing
isolated

We found nice riding conditions with 4-8" of new snow over a deeper storm layer. Theres quite a bit of newer snow in this area, but unfortunately it's all resting on a weak base. For the most part, sleds would stay on top, but we sank in below the Solstice crust layer and got stuck a few times. This weak snowpack foundation showed potential for avalanches in tests, and we observed a recent medium sized slide that probably ran on the same layer. Not the day to punch it up into steeper terrain.

Warming temperatures were beginning to change the riding conditions, and resulted in a handful of rollerballs and small wet loose avalanches during the day.

Minor cracking in the new snow at upper elevations. I felt one collapse when my partner rolled up next to me with his sled.

Weather

Wind Loading
light
Recent Snowfall
10-20cm

Cold temperatures below about 5,000ft, warmer above. Winds were moderate and sustained atop Table Mtn, drifting moderate amounts of snow in locally windy locations. Moderate rain on the north side of the pass on the way back down at 12:30.

Snowpack

On a NE aspect at 5,200ft, HS was 102cm.

The snow since the Solstice all blended together and it was difficult to pick out the 1/16 interface.

The Solstice crust/facet was down about 65cm, where we found a thin layer of facets above a decomposing crust. The facets beneath the crust were larger, striated and chained, and could debatably be called depth hoar. 

An ECT failed with 14 taps and propagated on and beneath the crust (ECTP, M 14).

Avalanche

Size
D1.5 R1
Aspect
E
Elevation
6000 ft

We only spotted one crown from a day or two prior. A number of rollerballs occurred during the day, some turned into small wet loose slides lower down at road level on the pass.