Grey Butte NE Aspects

A tour on Grey Butte saw about 1 in / hr of snow, moderate to strong SW winds, and evidence of wind loading on E and NE aspects. The rain crust from the 1/8/17 rain event was witnessed throughout all elevations, at a depth of 50-64 cm (20-25 in). Skis did not penetrate this layer and no whumphing was heard. A snowpit was dug on a sheltered ENE aspect of Grey Butte just below the weather station with the following characteristics:

Aspect: ENE

Angle: 30°

Elevation: 7976

Height of Snow (HS): 377 cm (148 in, 12.4 ft)

New Snow From 1/8 rain event: 64 cm (25 in)

New Snow From 1/6 storm event: 90 cm (35 in, 3 ft)

Stability Tests:

CT7; Sudden Planar & CT10; Resistant Planar @ 20cm

CT13; Resistant Planar; & CT14; Non-planar Break @ 40cm

CT21; Non-planar Break; & CT24; Sudden Collapse @ 70 cm

ECTN10 @ 20cm

ECTN16 @ 40 cm

ECTP27 @ 70 cm

Whereas stability tests on this aspect did not yield concerning unstable results, a similar aspect (NE, 35-40°) that was subject to strong SW winds yielded an easily controlled ski triggered avalanche (see pics). Controlled ski trigger caused a cornice fall which triggered a wind slab avalanche entraining loose snow beneath. Destructive size was about D1.5 -- might lead to burial. Crown was about 20 in.

Though visibility was poor, we think we saw signs of a what was probably a D1.5 avalanche that may have occurred early in the 1/6 storm cycle on the NW aspect of the ridge-line between Grey Butte and the weather station.

Skiing was great!