Observation: Bear Trap

Observation Date
1/11/2014
Observer Name
JB
Region
Salt Lake » Big Cottonwood Canyon » Bear Trap
Location Name or Route
Bear trap aspens
Weather
Sky
Broken
Wind Direction
West
Wind Speed
Light
Weather Comments
Warm, with periods of strong sun, light winds until 1pm when they ramped up to moderate.
Snow Characteristics
New Snow Depth
16"
New Snow Density
High
Snow Surface Conditions
Rain-Rime Crust
Snow Characteristics Comments
From the best I could tell it looked like a wind event followed by grauple and then freezing rain accompanied by a wind from the west. The snow surface had a pretty uniform rain crust of 1-2mm. The trees were all coated with a thin layer of ice on the west side. The crust was easily breakable and more loud than anything else.
Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Rapid Warming
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
A thick, dense slab seemed to have formed, but only the top 5 to 6 inches was reactive. Significant loading though.
Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments
The facet layer at the ground almost feels slightly wet and surprisingly cohesive, but about 10 cm from the ground larger 2-3mm, drier facets are a problem. Our pit at 9200 feet. NW on a 30 degree slope yielded a CT13 Q2 and much more scary a ECT12 Q1 on the same layer of well developed facets about 50cm from the surface.
Comments
Of interest was a skin track adjacent to the pit location we chose. It had been used today before we got there. It crossed a 35 degree slope with signs of wind loading. It was the easiest path on our desired route, but seemed too risky for myself and partners, but another party of four crossed with little to no conversation. Using good technique (one at a time) they crossed,with only the last person asking how we felt about the slope. It was an interesting observation of the heuristic elements that come into play. I am in no way passing judgement on this party. They crossed safely without incident and it very well may have been within their risk comfort zone. It did seem that at least one person in that party did not feel entirely comfortable with the route. I wonder if with the knowledge of the results of the pit (done a half hour after) if some or all of the group would have reconsidered route choice. I would like to re-interate that I bring this up only because following friends or spouses is such an easy and natural thing to do that it is easy to overlook the consequences.
Ice crust
Ice from branches
Today's Observed Danger Rating
High
Tomorrows Estimated Danger Rating
High
Coordinates