Observation: Little Cottonwood Canyon

Observation Date
4/11/2013
Observer Name
Greg Gagne
Region
Salt Lake
Location Name or Route
Upper LCC Periphery
Weather
Sky
Obscured
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Light winds out of the W/NW with occasional moderate gusts along ridgetops. -2C & presumably high dew point leading to a very damp feeling.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Damp
Snow Characteristics Comments

About 10 cms (4") new in upper LCC. Despite the occasional breeze, very little snow transport observed with some wind deposits along ridges. These were 5-10 cm thick soft wind slabs that would break out at most a meter from my skis.

Avalanche Problem #1
Problem
Wet Snow
Problem #1 Comments

The solar aspects should respond quickly to the onset of sun come Friday morning.

Comments

Wandered around upper LCC with very poor visibility. New snow was dense and bonded well to underlying snow surface (which on all but due North aspects was sun crusted.) There were some fresh wind deposits, but they wouldn't break out very far from my skis - at most about a meter (~3') and they were shallow (< 30 cms). The wind slabs from the Tuesday wind event are not sensitive at all. The dense new snow was difficult to even get to sluff, although I was able to get some wet rollerballs on a steeper southerly aspect that warmed despite the obscured sun. Overall mostly Low hazard, with a Moderate hazard in steeper wind-affected terrain or on steeper solar aspects.

This anti-Mark White photo highlights one of the better periods of visibility this morning.

This falls under the "small things amaze small minds" category: During a period of very poor visibility, I decided to dig a pit on a North aspect at 10000' to see how the upper elevation north-facing aspects look. For the past month or so I have been noticing the upper elevation North aspects still harbor a late winter snowpack with no signs of free water movement apart from some damp snow near the surface and a few melt-freeze crusts. HS was 270 cms, which was mostly a stout 1F slab.

More importantly, in the upper 2 meters of snow I was not noticing any crusts or interfaces between different grain sizes which would form a capillary barrier which would make it difficult for water to flow down through the snowpack.

I have never taken a full temperature profile so late in the season, so was curious just what such a profile would appear as. The following is an iPhone screenshot using AvyLab software.