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 Observations Explorer All Observations Avalanches Fatalities Weather Place Names Map Archives
Education
Avalanche Class List UAC Class List Online Classes Resources and Tutorials Avalanche Awareness Develop Skills
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: Willows

Observation Date
12/24/2018
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Willows
Location Name or Route
Willow Heights/PC Ridgeline/Will's Hill
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
Southwest
Wind Speed
Light
Weather Comments
Early morning dense cloud cover broke apart by 1300 hours for a brief period of intense sunshine, and then by 1600 the skies became overcast. Light snowfall at an S-1 rate accumulated to around 5 cm by the time it stopped snowing at 1230. Winds were light out of the WSW with no wind blown and or transport observed
Snow Characteristics
New Snow Depth
6"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
Variable conditions out there. Low angle southerly facing terrain above 9400 feet rode very well. The steeper lines in Will's were grabby with a 2 cm breakable wind crust below the 15 cm of settled powder from the latest few events. West facing exposed terrain and ridge tops had areas of wind scour. The best riding was in the sheltered terrain in areas traveled.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
Snow Pit at 9650 on a NNW aspect on the extreme rider's left side of Will's had the weakest structure I have yet to encounter in this winter. HS was 110, and there was a 40 cm thick layer of DH with a sandwich of 1.5 cm rain crust 30 cm up from the ground. So, the upper 8.5 cm of advanced dry facets were above the rain crust. The facets below the rain crust (on top of the ground) were at least 2.5 mm in size, dry and uncohesive except right below the rain crust. First attempt to isolate a column resulted in a VE score as I wasn't able to isolate it. The second attempt worked with a CT21 SC that was very sudden. Unfortunately due to time restraints and darkness looming I was unable to perform an ECT. But, the fact remains this snow structure is extremely weak, and it appeared to not showing signs of healing at all. This slope should be considered very suspect with the next significant load.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
See above, and though this problem has been mostly dormant for several weeks now, there appear to be many locations where it may still be an issue looming.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Same
Problem #2 Comments
Sustained winds with ample velocities continue to blow at the highest ridge lines, and sensitive wind slabs may still be an isolated issue of concern.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate