Observation: Big Cottonwood Canyon

Observation Date
3/2/2021
Observer Name
E
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Mid Big Cottonwood Canyon
Weather
Sky
Clear
Wind Direction
Southwest
Wind Speed
Light
Weather Comments
Traveled today in Mid Big Cottonwood Canyon between 7000 and 8400 feet. Cold morning temperatures with above normal highs in the pm. Very Light Wind Blown observed only near exposed ridge lines.
Snow Characteristics
Snow Surface Conditions
Faceted Loose
Melt-Freeze Crust
Damp
Snow Characteristics Comments
Northerly aspects with slope angles 25 degrees and greater holding good riding in settled powder with surface snow consisting of a mix of NSF's and SH. All other aspects getting damp, moist and wet, and the m/f Crusts will grow more everyday.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
30 cm of facets near the ground in areas with HS ranging from 110 to 180 cm. Biggest concern is the New PWL in Town. Activity noted since Saturday at the New Snow/Old Snow Interface has now transitioned from Storm Slab to Persistent Slab. Though it is only 10 to 20 cm deep, this will be a layer to keep an eye on when we get more load. It's distribution is only in Specific locations, and these are NNW, N and NNE protected terrain from any wind scouring, and the slope angles need to be 25 degrees and greater. It appears to be a result of the Melt Layer Recrystallization process. When the new snow came in it landed on a warm snow pack and the initial couple of millimeters bonded to the old surface, but above that the light density snow became the reactive layer that has been identified in many locations as an easy shear with some avalanche activity reported. Small grain facets were observed today in this layer with clean/easy shears still being reactive. Again, the overriding slab is only 10 to 20 cm at this point, but in the above cited Specific areas this issue may persist and these facets will likely continue to develop with the wide temperature swings we are experiencing. Just something to keep an eye on.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
Basal Facets appear to be dormant at this point, but the poor snowpack structure is still in place in many locations. Of note is the above cited weak layer at the old snow/new snow interface.
Avalanche Problem #2
Problem
New Snow
Trend
Same
Problem #2 Comments
Surface faceting appears to be increasing and the potential for Loose Dry Avalanches/Sluffing could be a concern in very steep confined areas where entrainment could possibly become an issue. This should be managable.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Coordinates