Observation: 10420

Observation Date
12/15/2025
Observer Name
John Lemnotis
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
Guardsman to 10420
Weather
Sky
Clear
Wind Speed
Calm
Weather Comments
Wind was calm for most of the day. Weather was unremarkable in terms of snow pack effect.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Melt-Freeze Crust
Snow Characteristics Comments

Pockets of dense loose existed where old wind slabs are breaking down on the ascent to 10410 and 10420 via guardsman pass. Otherwise, snow surfaces that were encountered consisted of MF crust that varied in how supportable they were.

Red Flags
Red Flags Comments
It's very interesting that there is actually a lack of red flags right now. Yes, it has been warm but the rapid portion has ended. Yes, we have garbage snow but overall there isn't a lot of structure for avalanches. There are limited areas of strong over weak. Most of the snowpack is faceting on polars and melting on solars. There is no snow available for transport after last weeks strong/extreme winds as well as extreme (for december) temps that left snow surfaces too bare or too warm to transport.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments

The PWL is inconsistent at best. Many areas where the PWL was present have lost structure for an avalanche. Best that I can tell the only areas that could produce an avalanche right now are where there were previously wind loaded a slab still exists on top of the 11/15 fc PWL.

Pit 1 - 9320' 40° NE 18° slope HS 35cm, CT 9 down 25cm on 3mm fc (somewhere between dry and moist) ECTN11 down 25cm. This pit was on the approach ridge from Guardaman to 10410

Pit 2 - 10320' 80° E 26° slope HS 45cm, CT12 down 25cm on 3mm fc (dry), ECTP21 down 25cm. This pit location was between 10410 and 10420, there was still a cohesive slab present.

Depth Hoar is defined as cupping or striations that are visible with the naked eye. No depth Hoar noted in the snowpack despite checking in several locations. Facets were big (on a relative scale) but the textbook presentation was not there.

Today's Observed Danger Rating
None
Tomorrows Estimated Danger Rating
None
Coordinates