Observation Date
1/9/2018
Observer Name
John Lemnotis
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
10420
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
Northeast
Wind Speed
Light
Weather Comments
Snow line was near 8500 mid day and wind was mostly light with moderate gusts on exposed ridge lines on the way to 10420 from guardsmans.
Snow Characteristics
New Snow Depth
4"
New Snow Density
High
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
Surface snow was shallow and damp at the trailhead and progressively got slightly better. The highest elevation I reached today around 10400' the snow was rather enjoyable to turn in, good base building snow, and good slab forming snow.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
With significant water content expected in the new snow we have almost all of the boxes checked. Natural avalanches continue to be reported and I suspect that some inadvertent human triggered avalanches happened today in the right zones. Cracking was normal when stepping above the skin track and one collapse was felt in a small meadow today. As everyone already knows our snowpack structure is bad, the storm snow that has already fallen will become more cohesive and topped off with more water content over the next couple of days. A slab on top of a persistent weak layer, now all it needs is a trigger.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
The persistent slab will be overwhelmed by the new snow and avalanches will have the ability to be large and potentially deadly. Low angle terrain is the norm this season and this trend is not changing with the current storms.
Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments
I noticed the most recent 4" of snow to be poorly bonded to the old snow surface on what might have been a density change, cracks initiated in this layer. The new dense snow is ideal for slab formation and there is more snow on the way. As the snow continues to pile up small releases from this layer and the storm snow to come could be enough to step down into the depths of the snowpack that is strictly facets.
Comments
I walked the ridge line to dig a bit and just poke around today. The snowpack HS was 95cm from the top down it started at fist getting progressively harder to 1 finger directly above the facets at about 40cm then the facets were fist plus all the way to the ground. When I performed an ECT the slab didn't seem quite cohesive enough to stress the facets but the CT easily showed that this is our primary layer of concern. I don't take the test results as something that makes me warm and fuzzy inside rather something concerning to watch for over the next couple of days as the storm progresses and beyond.
Video
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
