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Observation: Catherine's Pass

Observation Date
11/16/2024
Observer Name
Gagne
Region
Salt Lake » Little Cottonwood Canyon » Catherine's Pass
Location Name or Route
Catherine's Pass Area
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Northwest
Wind Speed
Calm
Weather Comments
Light snow flurries in the morning with a few peaks of sun that dampened south-facing slopes. Windless.
Snow Characteristics
New Snow Depth
6"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments
15 cms of new snow since Friday. I saw no evidence of wind-loading up to 10,500', although I suspect with stronger winds Friday night into early Saturday morning, there are a few wind drifts at the uppermost elevations.
HS (height of snow) above 9,000' is generally 15-75 cms. One pit on a wind-loaded slope near Sunset Peak measured 85 cms.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
Widespread faceted snow in the bottom 30 cms of snow on northerly aspects above 9,000'. Not an issue for now, but once we get enough of a load on top (additional snow and/or wind-loading), this weak layer may become reactive.
Snow Profile
Elevation
10,400'
Comments
Lots of snow pits looking at the weak structure we have on northerly facing slopes.
Pit #1 9,500' NW aspect - This slope had a wind slab above facets (and is now buried underneath the snow from overnight) and I got an ECTPV (full propagation upon isolation). I think this is an outlier as I have not seen many wind-loaded slopes, but the results made it clear that once we get more of a load and a stronger slab on top, we will likely have issues with the basal facets down near the ground.
Pit #2 10,300' N aspect - The bottom 20-30 cms was faceted, with the crust down near the ground deteriorating due to the faceting process.
Pit #3 10,500' N aspect - This pit was the deepest I've seen this season - 85 cms! The depth was due to some recent wind-loading with a 4F slab on top of the facets buried down near the rocks at the ground. ECTP21 failing in the facets, but another test was ECTN23 Q2. I suspect this is due to the lack of uniformity of the buried weak layer.
What does all this mean? We have a widespread weak layer on above about 9,000' in LCC on slopes facing at least northwest through northeast. (I have not looked at enough slopes facing west and east.) We currently don't have enough of a load on top to make the basal facets reactive, but we may find it reactive once we put enough of a load (through new snowfall and/or wind-loading).
For now, the biggest hazard is buried rocks, stumps, and downed timber.
Today's Observed Danger Rating
None
Tomorrows Estimated Danger Rating
None
Coordinates