Observation: White Pine

Observation Date
12/10/2019
Observer Name
Bruce
Region
Salt Lake » Little Cottonwood Canyon » White Pine
Location Name or Route
White Pine
Weather
Sky
Few
Weather Comments
Sunny and cold with increasing high clouds later in the day.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
A few inches of new, partially rimed snow on the surface skied fast on a supportable, stiffer layer. You didn't need to be on a steep slope to have fun. Cold temperatures preserved the snow well. Some surface hoar development from a clear night last night.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
No red flags except if you dig a snow profile or turn your pole upside down and probe to the ground, you will quickly discover a very weak layer of depth hoar near the ground.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
We returned to White Pine after being there 4 days ago. And yes, there's still monsters in the basement like the last trip. with several dozen probes with my ski pole turned upside down as I traveled, I easily detected the very weak layer of depth hoar near the ground. I dug a snow profile (attached) and found a very similar profile as last time with columns collapsing relatively easily with easy elbow taps and extended column tests propagating with medium elbow taps. On the other side of the stability coin, we now have a relatively thick, stout slab above the weak layer making any avalanches more difficult to trigger but if you do trigger one, it will create a large and very dangerous avalanche. I was also curious about the avalanche conditions on repeater slide paths because several people are triggering them these days. I was not able to dig or test one in the time we had. It's that clumsy time in an avalanche cycle when the hazard is slowly creeping down but there's occasional, pesky, booby traps lurking--with high consequences.
Of note, a couple other parties got away with traveling up, down and underneath several steep, large slopes that face north through east, plus travel in the bottom of a terrain trap--without triggering avalanches. I was not willing to follow their tracks. Skiing is just as good on gentler terrain.
Snow Profile
Aspect
Northeast
Elevation
9,800'
Slope Angle
30°
Comments
A couple other parties got away with traveling up, down and underneath several steep, large slopes that face north through east, plus travel in the bottom of a terrain trap--without triggering an avalanche. But I was not willing to follow their tracks.
Other parties in White Pine stuck to gentler terrain, the first photo on the apron of Tri Chutes and the second photo ascending the rocky rib at the top of the drainage.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
None
Coordinates