Avalanche: Bear Trap

Observer Name
Hardesty
Observation Date
Thursday, January 31, 2013
Avalanche Date
Thursday, January 31, 2013
Region
Salt Lake » Big Cottonwood Canyon » Bear Trap
Location Name or Route
Lower Beartrap
Elevation
7,800'
Aspect
Northwest
Slope Angle
40°
Trigger
Skier
Trigger: additional info
Intentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Weak Layer
Weak Layer
Facets
Depth
18"
Width
60'
Vertical
80'
Comments

Steep wind loaded slopes guard the meadows into Beartrap. They are great test slopes to look at mid elevation terrain. Weak snow from both early January and late January that has been well documented has been overloaded in localized areas with snow and/or wind. Both collapsing and cracking noted in walking above these steep test slopes.

Able to trigger new slides 8" deep in the new wind drifts. Collapsing indicated other problems...so with some additional prodding, able to trigger two 10-20" slabs that stepped down and ran on both sets of January faceted snow. These left a debris pile of 3-4' deep in the gulley. Had spotters below to keep an eye out for others heading up/down the drainage.

Collapsing/cracking noted from 7800'-8400' on northwest to northeast facing slopes. ECTs conducted on northeast facing slopes at 9000' produced full propagation (20 taps) that elicited failure on both old and newer January failure planes 14 (.5mm mixed forms) and 24" (1mm facets) deep. Two for the price of one. Of note, two other ECTs that I conducted in the same area produced no results. I'm inclined to throw away the 'stable' results and keep the 'unstable' results. Might live longer that way...

Comments

Note the loading from right to left. This was fundamental to the sensivity today.

Coordinates