Observation: Mill Hollow

Observation Date
Observer Name
Staples & Gile
Uintas » Mill Hollow
Location Name or Route
Mill Hollow to Duchesne Ridge
Weather Comments
Weather bounced back and forth between heavy snow and sunshine
Snow Characteristics
Snow Characteristics Comments
Warm dense powder
Red Flags
Red Flags
Recent Avalanches
Red Flags Comments
2 avalanches and shooting cracks
Avalanche Problem #1
Persistent Weak Layer
Problem #1 Comments
Facets on top of an ice crust about 1-2 feet deep. Mostly on sunny aspects where radiation recrystallization formed the thin layer of facets above the crust that was buried the night before Valentine's Day.
A layer of Surface hoar (frozen dew or frost) is buried on northerly facing slopes about 3 feet deep. I have been finding this everywhere I dig.
Avalanche Problem #2
Problem #2 Comments
They have steadily gotten bigger from sustained south winds. Don't get too close to them.
The Uintas don't have avalanches ripping out everywhere as in mid January, but there are definitely a few weak layers that worry me.
We looked at the recent remotely triggered slide and then triggered another both on east facing slopes near treeline. These broke on a layer of facets above a crust. I think this layer got enough warmth and sun last Saturday and Monday that it's not an issue on due south facing slopes. Certainly it's an issue on East and West and likely Southeast and Southwest.
Then we looked for a west facing slope but ended up on a NW facing slope where I didn't think we'd find a reactive Valentines weak layer. What was surprising was to find the facets without an ice crust that both produced unstable test results (ECTP10) and produced a shooting crack (photo below).
And again, as in every northerly facing pit, I found a buried layer of surface hoar with some of the largest crystals I've seen yet. (Photo below).
Finally we had a close call with cornices. We triggered a massive cornice fall...like the size of a school bus. We thought we were far enough away because we didn't realize how big they were. They broke right at our skis. Clearly we were right on the line, and we were on the right side of it, but we had no margin for error and I'd say we just got lucky.
Today's Observed Danger Rating
Tomorrows Estimated Danger Rating