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Observation: Mineral Fork

Observation Date
2/3/2019
Observer Name
Meisenheimer / Clark
Region
Salt Lake » Big Cottonwood Canyon » Mineral Fork
Location Name or Route
Mineral Fork Ridgeline
Red Flags
Red Flags
Wind Loading
Red Flags Comments
Wind loading was the most obvious red flag. Lots of wind loading on the north and east aspects off the upper ridge line. Winds were strong enough to move snow around well off the ridge lines and I noted plenty of transport on the mid elevations as well. It did not seem the wind was able to whip up the heavy dense snow into a slab. I walked about 1/4 mile of the ridge and had no cracking or collapsing.
Avalanche Problem #1
Problem
Wind Drifted Snow
Problem #1 Comments
Even though I didn't see any cracking across the upper ridges I was not willing to test my theory and drop into the steeper northeast facing lines. It was very evident they were becoming more and more loaded by the wind. Perhaps these slopes were not loaded up enough - just yet. With more snow and wind on the way this could be a different ball game tomorrow and into Tuesday. I am sure the higher elevations that received more snow in the 10-12'' range wind slabs are an issue.
Avalanche Problem #2
Problem
Persistent Weak Layer
Problem #2 Comments
Unfortunately, I found buried and preserved near surface facets (NSF) in all four of my snowpits today. They are buried and preserved underneath the 4-6" of new snow that fell in Mineral Fork. I was finding NSF on all of the northerly facing slopes above about 8,000' in elevation. Below that, it was soaked by the rain. I lost the rain crust at 8500' in elevation.
I did perform 4 different ECT tests with no results. However, I think if you added another 12-18" of new snow on top of this layer you would see your column propagate a crack within this layer. We need to keep an eye on this as it might become tricky with incremental loading over the next several days. See the avalanche from 10,420 from today here.
Comments
The first photo: is my snowpit from a NE facing slope at 8,100' in elevation. The rain crust capped the NSF layer leaving them dry and preserved just underneath this crust. The rain crust in this location was not supportable and could easily become overloaded with more weight on top. I did not like seeing this set up for the area. We will have to wait and see if it become an issue. ECT were negative. However, with a shovel shear test the rain crust would fail in the faceted snow with gentle taps on the bottom of the shovel and come sliding off with ease.
The second photo: was dug just a few hundred feet higher when I noticed the rain crust was gone. Here I found about 6-8" of new dense snow resting on NSF. Again, my ECT was negative but the shovel shear tests reveled the upper 6-8" of new snow was sliding easily on this layer. The only thing we can do for the next few days is to dig and track this layer. It's super easy to find and it only takes 5 mins to dig down about 1-2' and perform a quick ECT test. If we start seeing this layer propagate then we know something is up.
ECT = Extended Coulumn Test. If you need to brush up on how to do an ECT test watch this video HERE.
It was a nice day to be out in the mountains with the wind on your face and new snow falling at times. Adam Clark snapped a nice photo of me walking on the ridge.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable