Observation Date
12/5/2017
Observer Name
Mark Staples
Region
Salt Lake » Little Cottonwood Canyon » Grizzly Gulch
Location Name or Route
Grizzly Gulch
Weather
Weather Comments
Clear, cold and sunny - perfect weather for faceting. Similar weather should continue all week.
Snow Characteristics
Snow Characteristics Comments

The greatest hazard continues to be hitting rocks and stumps which are now covered by the new snow from Sunday/Monday

Avalanche Problem #1
Problem
Persistent Weak Layer
Problem #1 Comments

Persistent slab avalanches seem unlikely now, but given the load of new snow and faceted snow underneath - I wouldn't trust the snowpack too much. There are a variety of weak layers on NW, N and NE facing slopes.

  1. Big facets/depth hoar at the ground
  2. Facets under a crust that formed during very warm weather around Thanksgiving
  3. Facets on top of this crust. Snow that fell Monday, Nov 27 on top of this crust became faceted

Strong winds on Sunday may have scoured the thin faceted layer on top of the Thanksgiving crust and and this layer only exist on sheltered slopes.

Bottom line - It doesn't really matter. There are plenty of faceted layers and one or more crusts. More importantly, the next week of high pressure will facet the snowpack even more. Faceting in the new new snow will create a persistent slab avalanche problem on a wider range of aspects and elevations.

Heads up - If we get a windy day soon, it could overload many slopes and cause avalanches on some of these faceted layers. There was a small avalanche today at a ski area. It broke on a low elevation, north facing slope in a place loaded by a snow gun. This is a heads up that we would likely see avalanche activity and unstable conditions if we get a really windy day that transports a lot of snow.

Snow Profile
Aspect
Northwest
Elevation
9,100'
Slope Angle
26°
Comments

I was surprised to get and ECTP10 and ECTP8. These are extended column tests that break and fracture (Propagate) across the full length of the column - a bad sign. I didn't think they would break on just wrist taps. These test failed on a thin layer of facets on top of the Thanksgiving crust. Fortunately this layer does not exist many places due to strong winds that blew just before the storm arrived. HOWEVER, I didn't have to look very hard to find it which tells me it's lurking out there.

Photo below of snowpit wall for reference.

Second pit. Not really enough snow to recreate. This is a SW aspect and I'll be curious how this looks after the next week of high pressure.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate