Observation: Big Cottonwood Canyon

Observation Date
12/31/2025
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Upper Big Cottonwood
Weather
Sky
Clear
Wind Speed
Calm
Weather Comments
Unseasonably warm again today with 8000' temperatures hitting 50 degrees. In the upper elevation shady terrain the low angle sun kept the temperatures from escalating past the mid 30's. Overnight lows continued to dip below freezing at most mountain locations.
Snow Characteristics
Snow Surface Conditions
Powder
Dense Loose
Faceted Loose
Wind Crust
Melt-Freeze Crust
Rain-Rime Crust
Damp
Snow Characteristics Comments

Everything can be found out there, yet the most interesting thing is how the "Facet Factory" has been operating in full swing. Skin trails used yesterday had a thin layer of NSF's that made for slippery travel on the steeps. Then entire snowpack is faceting above the rain crust, and in many places directly below the rain crust as well. Regardless, the riding continues to be good on the shady aspects at mid and upper elevations on steep and low angle terrain; and in areas housing at least 20cm of settled storm snow you can make turns without carving down to the rain crust. As the days progress beyond last weekends storm the settled storm snow continues to become more cohesive and is beginning to exhibit soft slab structure with minimal/insignificant cracking.

Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
See above for Poor Snowpack Structure in the upper layers of the snowpack. Dry basal facets continue to be identified by many observers.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments

Still waiting for todays observations to see if there were any more human triggered Persistent Slab avalanches. The testers have been out in full force he past few days without any more activity besides the Sunset avalanche that occurred 3 days ago. Avoidance of steep/shallow/rocky terrain in the upper elevations where the rain crust is thin may be wise. Any significant new loading in these zones may Likely overload these slopes. If tomorrows forecast verifies for the upper SWE values the danger will be increasing on all aspects and elevations with the mid and upper elevation polars PWL's becoming reactive. The most significant danger out there continues to be "Slide for Life" potential on the slick rain crust.

Did not travel in any areas receiving direct solar.

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