Widespread buried surface hoar instability

CB Avalanche Center 2016-17 Observations

Location: Crested Butte Area
Date of Observation: 01/24/2017
Name: Alex Banas, Donny Roth
Subject: Widespread buried surface hoar instability
Aspect: North East, East
Elevation: 10,800′

Avalanches: Intentional ski cuts produced the following:
Multiple SS ASc- R1-D1-I First bowl
Multiple SS-ASc-R2D2-I Second bowl
I think about 9 of these in total from first and second bowl. Some of these avalanched on slopes as low as 32*

We noticed one skier triggered D2 avalanche in 3rd bowl from yesterday.
Weather: Scattered skies with calm winds in the morning transitioning to overcast skies with moderate down valley (gothic) winds in the PM. Snowing s-1 at 1130 transitioning to s3 at 1430. Air temps in the high teens getting colder in the afternoon.
Snowpack: Touchy slab avalanches failing on the 1/19 surface hoar interface observed on the E-NE side of snodgrass today. All avalanches and shooting cracks failed 45-55cm down on the preserved surface hoar layer. This soft slab seems to be stiffening up throughout the day as shooting cracks increased in size and ski quality went down. The sensitivity to this instability is on the rise. This persistent weak layer is sitting above a bomber mid pack from our early january mega storm of 1f rounding facets. We did not notice any signs of blowing or drifted snow from the 1/23 wind event as we expected.