Avalanche: Catherine's Pass

Observer Name
Greg Gagne
Observation Date
Saturday, November 18, 2017
Avalanche Date
Friday, November 17, 2017
Region
Salt Lake » Little Cottonwood Canyon » Catherine's Pass
Location Name or Route
Catherine's Pass Area
Elevation
10,000'
Aspect
Northwest
Slope Angle
37°
Trigger
Skier
Trigger: additional info
Remotely Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Weak Layer
Weak Layer
Graupel
Depth
15"
Width
100'
Vertical
250'
Comments

This avalanche occurred likely during a period of high PI and quickly overloaded a 5 cm (2-3") layer of graupel. Am unsure if was a natural or skier-triggered slide as there may have been some old ski tracks adjacent to the slide. (Any ski tracks, as well as the bed surface) had filled in with 5-10 cms of storm snow.

In speaking to Mark Staples afterwards - he said it perfectly "(despite the weak layer of faceted snow near the ground), the graupel was the weakest layer."

[EDIT - Updated information is that this was a skier-triggered slide that occurred during a period of intense precipitation on Friday afternoon. The skier reported skiing the slope from the safety of trees on the skier's right of the slide path. Midway down their run, the steep slope adjacent to them remotely avalanched.]