Observation: Cardiff Fork

Observation Date
2/17/2021
Observer Name
McKinley Talty
Region
Salt Lake » Big Cottonwood Canyon » Cardiff Fork
Location Name or Route
Cardiff Fork
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
West
Wind Speed
Calm
Weather Comments
Skies broke at the Doughnut Falls TH for an hour or so around 14:00 then jumped right back into S2 precip. Air temp at 14:30 was 18 degrees F.
Snow Characteristics
New Snow Depth
2.5'
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
Lots of cracking within the new snow when walking off trail.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Cracking
Poor Snowpack Structure
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments
New snow was not well bonded to the new/old snow interface. Saw lots of loose-snow slides in steep terrain as well as glimpses of massive storm-slab crown lines when clouds broke to allow visibility.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments
Facets at the ground are still a major concern despite being buried deep after this new snow. If one does find a trigger point to activate this layer, the resulting slide will likely not be survivable.
Snow Profile
Aspect
Northwest
Elevation
7,400'
Slope Angle
18°
Comments
Went up to Cardiff Fork just to investigate the new snow, had no intention of skiing or traveling below any steep slopes and consequently did not make it very far. However, it was nice to walk in some deep snow.
I dug a snowpit on a NW facing slope at 7430' and found the height of snow to be 185cm. New snow from 2/12/21 stacked up around 80cm and seemed fairly right-side-up, however it was bonding poorly to the old snow interface (see video) and within the new snow at the 2/15 storm-break (see test results in SnowPilot graph). There were multiple layers below the new snow with large jumps in layer hardness, making for a fairly complicated snowpack (see photo 1).
While the main concern for today was new snow instabilities, facets near the ground are still a major worry. Photo 2 shows large faceted grains that lurk deep below the snow surface. I think it's fair to say the PWL problem has now turned into a Deep PWL problem, which scares me even more. While it may be harder to get this layer to react after the recent storm, all it takes is a shallower trigger point for this dragon to wake up with a fiery vengeance.
Video
Today's Observed Danger Rating
Extreme
Tomorrows Estimated Danger Rating
High
Coordinates