Observation: Guardsman Pass area

Observation Date
3/5/2022
Observer Name
Gagne
Region
Salt Lake » Big Cottonwood Canyon » Guardsman Pass area
Location Name or Route
Guardsman Pass Zone
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
South
Wind Speed
Light
Weather Comments
Periods of light snowfall with light winds along exposed ridges.
Snow Characteristics
New Snow Depth
2"
New Snow Density
Medium
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
Above 9,500' new snow was somewhat dry with damp snow below that elevation. New snow has bonded well to existing snow surfaces.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
Poor snowpack structure with slab on top of Jan/Feb facets down 30-40 cms.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
There is weak/faceted snow down 30-40 cms on northerly aspects at the mid and upper elevations. The snow that fell on top of this weak layer 10-14 days ago is now a stronger, more-cohesive, 1F slab. I was getting full propagation extended column tests (ECTP12-15) with the failure plane this layer of faceted snow.
With the potential of 1"+ of water-weight by later Sunday, we are likely to see some avalanches failing on this PWL layer.
Photo below shows this structure of stronger snow on top of weaker snow. We will only be adding more of a load on top of this poor structure.
Comments
Hopefully this storm materializes! The snow that fell overnight Friday into Saturday was somewhat dense and had bonded well to the existing snow surface. If we do get periods of heavy snowfall into Sunday, I am expecting the weakest snow may initially be within the storm snow. Very warm weather the past several days has left dense, warm snow at the old snow surface with widespread heat and sun crusts under the strong March sun. Avalanches involving new snow may run on these crusts.
I was seeing plenty of weak, faceted snow on northerly aspects from the Jan/Feb drought, and the slab on top has strengthened and is now more cohesive than it was a week ago.
This combination will make for some tricky snowpack assessments on northerly aspects where I think the stronger slab on top of the facets may be able to support a load on some slopes, but on other slopes where the slab isn't as strong it may be possible to trigger deeper avalanches failing on thie PWL.
Video
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable