Observation: Big Cottonwood Canyon

Observation Date
12/27/2020
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Mid Big Cottonwood Canyon
Weather
Sky
Broken
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Scattered skies in the am filled in by 1400 and became Broken. Light WNW winds throughout the day with no Wind Blown observed at the Lower Elevations. Temperatures continued to be in the moderate range for this time of year.
Snow Characteristics
New Snow Depth
2"
New Snow Density
Low
Snow Surface Conditions
Powder
Faceted Loose
Snow Characteristics Comments
Good Powder riding on Moderate to Low angled slopes in untracked terrain.
Red Flags
Red Flags
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Widespread Collapsing and Cracking experienced at the lower elevations traveled. Poor Snowpack Structure in place even at 7500 feet. Snowpit at 7450, NNW, HS: 60 cm, 25 degrees: CTM SC at 12 cm down, (Weak Layer: facets below Rime Crust), ECTP18 at 28 cm down, at the old snow interface from the event that began on December 12, in large grained (2.5 mm) facets. New snow appeared to be well bonded to old snow, most likely as a result the warm pre-storm temperatures.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
See above, As reported a week ago from similar elevations in LCC, this Persistent Slab Avalanche Problem exists as well at the Lower Elevations on at least NW, N and NE aspects. Storm forecast for next 36 hours appears to have been downgraded, yet if precip during this period hits 1 inch SWE, we may likely experience another Natural Avalanche Cycle even in these Lower Elevations.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #2 Comments
Lower Elevations were definitely not experiencing the same High Velocity Winds that the Upper Elevations were over the past 36 hours, It appeared that the Upper Elevation Winds died down throughout the day on Sunday, and any lingering Wind Slabs may have begun to settle out and become less reactive by the end of the day; yet they are still suspect where they exist on buried weak snow on the upper half of the compass. In these specific areas the Danger most likely was Considerable today. Despite the widespread poor structure, and with no Naturals reported for over 48 hours, the Danger in other locations appeared to be High Consequence Moderate. If we hit the high end of the forecast for the next 36 hours,, the unusual E and ESE may contribute to elevating the Danger rating to a solid Considerable on all aspects at mid and upper elevations.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable