Observation: Bear Trap

Observation Date
2/19/2016
Observer Name
Bruce Tremper
Region
Salt Lake » Big Cottonwood Canyon » Bear Trap
Location Name or Route
Beartrap fork to head of drainage
Weather
Sky
Scattered
Wind Speed
Moderate
Weather Comments
I was out with a group of friends so sorry for no photos and lack of detail. Sunny in the morning with increasing clouds and wind later in the day.
Snow Characteristics
New Snow Depth
5"
Snow Surface Conditions
Powder
Snow Characteristics Comments

5 inches of dense, creamy snow--dust on crust in the morning when the rain crust was frozen but as the sun softened up the snow later in the day, all the snow on the sun exposed slopes got pretty manky. You could feel the rain crust at lower elevations but you got above it around 9,000' where the new snow sat on a spongy, old base. There was a lot of graupel at the base of the new snow. It felt slabby in the wind drifted areas but the graupel bonded up faiirly well because of the warm temperatures.

The wind from yesterday's violent cold front caused ferocious, possibly historic, wind that not only blew all the snow at most elevations, but it hewed down hundreds of trees. I personally came upon perhaps 50 big trees that were blown over, so there must have been a couple hundred in Beartrap drainage alone. There was probably a dozen trees across the summer trail, many of them very large. The trail crew will be busy this spring.

Red Flags
Red Flags
Wind Loading
Rapid Warming
Avalanche Problem #1
Problem
Wind Drifted Snow
Problem #1 Comments

The aforementioned, nukin wind yesterday redistributed snow at most elevations, especially the upper elevations. You could see huge wind ripples on many slopes. Beartrap fork is not exactly the best place to observe wind loading but there was a lot of damage even there. I was suspicious of the slabs at first because they rested on a layer of graupel on top of a pre-existing melt crust. But the temperature was warm enough so that the graupel healed up pretty quickly and I could not find many places with cracking and nothing was moving.

The wind that came up later in the day looked like they were building fresh wind slabs but I was with a larger group of friends and some needed to be in town early so we left around 2 pm.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

The strong sun this time of year made the snow on the sun exposed slopes manky in a hurry. I could see quite a lot of rollerballs on the steep, lower elevation terrain.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate