Salt Lake » Little Cottonwood Canyon
Location Name or Route
Upper LCC Periphery
An overall Low danger. Today, I focused my field work on the layer of faceted snow on top of a sun crust that formed last week during a brief period of sunshine and was buried by storm and wind-driven snow this past weekend. This was the weak layer on several avalanches over this past weekend, including a large avalanche on the shoulder of Wolverine.
Today I dug about 12 pits on steep aspects facing southwest, south, and southeast and overall most pits showed the weak layer either not present or gaining strength where it is present. One pit on a southwest aspect got a full propagation down 40 cms failing on this weak layer - ECTP19. All other pits were either ECTX (no fracture) or ECTN, fracturing on the weak layer, but not propagating. From what I saw today, we are moving in the right direction and the current PWL problem that is located on these solar aspects may be removed from the forecast soon. My biggest hesitation is that upper Little Cottonwood has lived in a snow globe for the past two months and saw very little sun last week, when this weak layer formed. It is possible that where I was looking in upper LCC, the weak layer was not that widespread, but that it may be more widespread in areas such as Big Cottonwood, Millcreek, and Lambs Canyon; areas that likely had more sunshine early last week.
There also was a small skier-triggered avalanche on southwest-facing Patsy Marley that occurred late Wednesday or early morning Thursday. Although I could not get that close to it, the avalanche was about 30-45 cms deep and 60' wide and very likely failed on this PWL. This is an indication that the weak layer may still be reactive in isolated areas.
Current snow surface consisting of some surface hoar on shady aspects and radiation recrystallization (RR) on sunny aspects;
Pit showing the general location of the facet/crust combination which is generally down 30-45 cms, although deeper (up to 60 cms) in some places;
Photo of skier-triggered avalanche on southwest-facing Patsy Marley.
Today's Observed Danger Rating
Tomorrows Estimated Danger Rating