Variable Sensitivity

CB Avalanche Center 2018-19 Observations

Location: Crested Butte Area
Date of Observation: 12/07/2018
Name: Evan Ross, Zach Kinler

Subject: Variable Sensitivity
Aspect: North East, West
Elevation: 9,800-11,000. BTL

Avalanches:

SS-AS-R1-D1.5-O BTL West Facing Aspect. Crown about 60cm with only about 5-10cm of 4f slab in there. Failed on large facets on the ground.

D2.5? Very large avalanche off an Above Treeline easterly aspect of Gothic mountain. Could only see parts of the crown and never saw the debris. Probably ran within the last 24hr.

SS-N-R1-D2 ATL on the southerly face of Mt Bellview. Looked like it ran in the upper snowpack as a windslab. Probably ran within the last 24hr.

Belleview Mountain South: SS-N-R2-D2-I (this is a different mountain than the one above.)

SS-N-R1-D2 ATL on an easterly aspect of Baldy Mountain. . Probably ran within the last 24hr.

Numerous small loose snow avalanches that ran today on upper elevation steep and rocky southerly faces.

Weather: Fog in the upper Crusted Butte Valley in the morning and moving out around midday. Otherwise few clouds. Calm winds. Good solar.
Snowpack: Variable sensitivity to the PS avalanche problem. On BTL north east, we got some good collapsing and shooting cracks up to 15ft on slopes in the lower 30 degree range. The couple of steeper slopes over 35 degrees we visited had previously avalanche this winter. The slopes that avalanched earlier in the winter had refilled and were tough to distinguish between those that hadn’t avalanched. In a profile on one slope that had previously avalanche, the HS was about 20cm’s less, lacked a slab, but maintained about 5-10cm of large grained facets on the ground. So difficult to tell which slopes or where on a slope the PS structure was present and currently reactive.

On a westerly aspect BTL and protected from the wind, the snowpack structure mirrored that of a NE aspect. Otherwise, the more open westerly aspects appeared thin and sharky.

Photos: