Observation: West Bowl

Observation Date
01/11/2018
Observer Name
Cody Hughes

Region:

Location Name or Route
Silver Fork
Weather
Sky
Broken
Wind Direction
West
Wind Speed
Calm
Weather Comments
Beautiful morning in the mountains. Mostly calm winds however a few small gusts here and there along the upper elevation ridges. Minimal wind transport where we were. Sun poking through at times opening up visibility and making the skiing that much better.
Snow Characteristics
New Snow Depth
6"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments

Right side up storm produced supportable surfy conditions on the surface. Finally felt like winter out there today in the Wasatch!

Red Flags
Red Flags
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
We were keeping good spacing on the first few laps and especially the first lap breaking trail back up west bowl and didn't experience any collapsing or cracking. On our fourth lap we were too close together and nearing the top and got a big collapse with a shooting crack by the skin track. Poor snowpack structure is obvious if you put your shovel in the snow.
Avalanche Problem #1
Type
Persistent Slab
Trend
Same
Problem #1 Comments

The culprit layer I am finding to be most reactive is the faceted snow grains that formed during the high pressure in early and mid December sitting just underneath the Christmas cycle. I found this 65 cm from the ground on a NE aspect in upper Silver 
Fork at 10,000ft. We were finding a small 1 finger slab on top of this layer but 4 finger to fist hardness snow above that all the way to the surface. These types of avalanches can be triggered from below, above or adjacent to the steeper terrain especially in areas where you are able to find a more dense slab sitting on top of the PWL's.

Avalanche Problem #2
Type
Wind Slab
Trend
Same
Problem #2 Comments

More dense hard wind slabs along the exposed mid and upper elevation ridgelines are sensitive and seem to be likely to step down to older faceted snow deeper in the snowpack. These wind slabs have the potential to break deeper and propagate further than expected. With the winds forecasted to increase over night I expect this danger to remain the same.

Video

NE 10,000ft Upper Silver Fork on a 36 degree slope. 

HS - 150 cm 

ECTP 20 @ 65 cm from the ground. Failing on facets formed during Decembers high pressure.

** You can tell I get a little stoked on getting this result because the previous test resulted in an ECTN and I knew I could get results. The second test shown here I was able to get propagation across the column.

 

Video

Same pit location as ECT above.

CT 12 Q1     ** I say Quality 1 sheer because it was a sudden collapse and was sudden planar. It popped and cleanly sheered but did not fall all the way out. Either way we get the idea.

Today's Observed Danger Rating
High
Tomorrows Estimated Danger Rating
Considerable
Snow Profile Coordinates