Sign Up for the Utah Snow and Avalanche Workshop (USAW) on December 7th!
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 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: Silver/Days

Observation Date
12/23/2023
Observer Name
Kelly
Region
Salt Lake » Big Cottonwood Canyon » Silver/Days
Location Name or Route
Flagstaff-Days-Silver Fork
Weather
Sky
Broken
Precipitation
Light Snowfall
Wind Direction
West
Wind Speed
Light
Weather Comments
Morning started out with overcast skies and moderate snowfall. Clearing around 3pm and socked back in around 4pm. Winds were mostly light blowing from the west. The wind picked up and transported a bit more snow later in the afternoon blowing from the northwest.
Snow Characteristics
New Snow Depth
6"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
New snow was 6-8" deeo in most locations. Old snow surface was a mixed bag of crusts in places I traveled. The solar aspects (S-W) were stiff melt-freeze crusts with new snow on top and the polar aspects (N-E) had a lighter crust underneath the new snow. Some wind-drifted snow isolated to the ridgetops. Around 9-10am I noticed some rimed stellar crystals. All the dry loose avalanches I saw were running on a density change within the new snow that I suspect was rimed crystals.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments
Photo of natural dry loose avalanches ( most likely running on a layer of rimed stellars) on Silver Fork Headwall. I noticed the same dry loose characteristics in steeper terrain in Days Fork and saw observed some spontaneous dry loose avalanches on east facing terrain with an uptick in winds around 330pm. These were dry loose point releases were about 4-6" deep and would not have been enough to push a rider over unless it was in extremely steep terrain with room to run. On a a steep east facing gully feature at 8700' I was not able to trigger any avalanches in the new snow.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Same
Problem #2 Comments
I noticed some wind-drifted snow isolated to the ridgelines (within 15' of the ridgelines) where there was some minor cracking. There is now snow available for transport and is something I would watch for in the next few days.
Snow Profile
Aspect
North
Elevation
10,100'
Slope Angle
41°
Comments
This snowpit was on a steep 41° slope on a due north facing piece of terrain in Hideaway Park. I believe that the steepness of the terrain is what allowed for failures with propagation with such low numbers including one failure when cutting the back out. These failures show us that we have poor structure and we are not seeing avalanches on this weak layer. As Greg mentioned we had one PWL avalanche that was explosive triggered on December 21st, but the last reported avalanche on this PWL layer was December 9th in the Wilson Chutes. I don't trust this PWL layer. While temperature gradient in the snowpits I have dug shows healing in this layer. This structure is still very poor and any additional load (either new snow or wind) is suspect in my mind. The immediate concern is new snow and wind-drifted snow (upper level) instabilities and I will keep the PWL layer near the ground in the back of my mind when making terrain choices for the time being.
Video
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Low
Coordinates