Observation: Mill Hollow

Observation Date
2/19/2021
Observer Name
Mark Staples
Region
Uintas » Nobletts » Mill Hollow
Location Name or Route
Campbell Hollow
Weather
Sky
Broken
Wind Direction
West
Wind Speed
Calm
Weather Comments
Surprisingly calm winds. Even before today, it appears that winds have done minimal drifting of the new snow. Exposed ridgelines had seen some winds and some drifting but there was still reasonable soft snow and not the typical hard, wind scoured snow on top of ridges.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
The PWL (persistent weak layer) is very easy to find. In uncompacted areas, you still sink deep into the snow and basically to the ground when you step off your sled. Most places have a decent slab 2-4 feet thick on top of this PWL. This slab is getting much more supportable for skis and sleds.
The difference between low elevations and higher elevations is the thickness of the slab.
Snow Profile
Aspect
East
Elevation
9,700'
Comments
We did ECT (extended column tests) in mulitple locations. In general, all are propagating (a bad sign) but they area all requiring taps from the shoulder. In the snow profile above it was ECTP28 which is pretty hard force. The facets that make up the PWL remain very weak, however, they appear to be "adjusting" to the load/stress of last weekend's snow. ECT's are requiring more force to fracture. However, recent avalanche activity trumps any snowpack test results.
This avalanche that happened further north near the south fork of the Weber River is a good example.
I am kind of thinking that to trigger a slide, you need to find areas of thinner snow like the Mill Hollow avalanche. Areas with thicker snow will be harder to trigger. In fact, areas with thicker snow may be able to see a number of tracks before producing an avalanche.
The photo below shows an area with moderate snow depth that is graphed above.
Video
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates