Fall Auction is now live! Check it out now
Ad
The National Forest Service Logo
icon-add Observation
Forecasts
Logan Ogden Salt Lake Provo Uintas Skyline Moab Abajos Weather Archives How to read the forecast
Observations & Avalanches
Submit Observation NEW - Observations Explorer All Observations Avalanches Fatalities Place Names Map Archives
Education
Avalanche Awareness Develop Skills On-Snow Courses Resources and Tutorials
Events
Store
About
Contact Who we are Core Values Staff Board of Directors Past Forecasters Sponsors Annual Reports Sign In
Blog
icon-add Observation
Donate / Join

Observation: Mill D North

Observation Date
3/9/2022
Observer Name
Gagne
Region
Salt Lake » Big Cottonwood Canyon » Mill D North
Location Name or Route
Mill D North Circuit
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Moderate and sustained gusts out of the northwest along exposed ridges. Periods of moderate snowfall.
Snow Characteristics
New Snow Depth
18"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
Estimated 30-45 cms storm snow.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Surprisingly did not get any collapsing.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments
Plenty of cracking in the new snow on steeper test slopes. There is a much-advertised density inversion within the storm snow and on all aspects I was finding the most reactive weak layer to be the new snow/old snow interface. Decreasing danger as storm snow instabilities should settle out quickly.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments
I dug plenty of pits on northerly aspects where the Jan/Feb facets are present and everything was ECTN, either within the storm snow or at the interface with the old snow.
Comments
The most reactive weak layer I was finding today on all aspects was the interface between the new and old snow. On steeper slopes I was able to get clean shears on this weak layer when isolating a column (CTV). All extended column tests were ECTN (collapse but no propagation). However, I did get one full propagation (ECTP22) on a south-facing aspect at 9,000 where it appears the storm snow from Saturday night/Sunday morning is now a layer of decomposing fragments (DF's) as well as the early stages of faceting. This weak layer is on top of a crust that had formed prior to snowfall on Saturday.
With over 2" of water in places and a PWL that is now down 45-60 cms (likely deeper in the upper Cottonwoods) it definitely is time to step back and see how the PWL adjusts to this rapid load.
Today's Observed Danger Rating
High
Tomorrows Estimated Danger Rating
None
Coordinates