Observation: Brighton Perimeter

Observation Date
4/6/2021
Observer Name
E
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Overcast throughout the day until 1400 when the cloud cover broke and intermittent solar was occurring. Temperatures changed drastically from the past week with daytime highs in the lower 20's at Upper Elevation. Winds swung around from SW to WSW to W by the end of the day, and they were in the Moderate to Strong Category even well down in the drainages. Upper Elevations were experiencing these same velocities yet they were more sustained.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Damp
Snow Characteristics Comments
There was 6 inches at 0600 at most elevations with Moderate Snow Fall Rates throughout the mid morning hours. HST in the Snake Creek area was 8 inches, while the areas near Twin Lakes received at least 12 inches. The storm came in on a warm snowpack and there was good bonding to the old snow surface.
Wind Slabs of up to at least 3 feet were observed in the Snake Creek area and these slabs were soft and reactive in the early morning hours. In other areas the Winds had swept away all the new snow down to the old crusty snow surface.
By 1400, there appeared to be a slight greenhousing event that dampened the new snow on all low angle slopes and especially the E and S aspects. This issue appeared to be spotty with 8000 foot slopes in the Silverfork area escaping this damage.
Overall the riding was incredibly good with slopes 25 degrees or less offering a bottomless feeling. Steeper slopes were scratchy, but still good.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Red Flags Comments
One small pocket of Storm Slab (that had a contributing factor of Wind Loading) observed on a ENE steep convex terrain feature at 9800. In the very early morning hours there was a Reactive/Sensitive Storm Slab that was in a light density break directly above the bonding area of the new snow to the old snow surface. This layer settled out quickly by the mid morning hours. There was also a Sensitive Loose Dry break that was reactive on steep slopes throughout the morning hours and this was 3 to 4 inches down. This Likely settled out in the afternoon after departing at 1400.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments
See above regarding Wind Slabs, and the Upper Elevation Winds are still in the Strong category at 1800 out of the NW.
Avalanche Problem #2
Problem
Wet Snow
Trend
Increasing Danger
Problem #2 Comments
This was not a problem today, but will Very Likely be an issue to contend with on Wednesday.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable