Ad
The National Forest Service Logo
icon-add Observation
Forecasts
Logan Ogden Salt Lake Provo Uintas Skyline Moab Abajos Weather Archives How to read the forecast
Observations & Avalanches
Submit Observation Observations Explorer All Observations Avalanches Fatalities Weather Place Names Map Archives
Education
Avalanche Class List UAC Class List Online Classes Resources and Tutorials Avalanche Awareness Develop Skills
Events
Store
About
Contact Who we are Core Values Staff Board of Directors Past Forecasters Sponsors Annual Reports Sign In
Blog
icon-add Observation
Donate / Join

Observation: Brighton Perimeter

Observation Date
12/10/2016
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter/Silverfork Area
Weather
Sky
Obscured
Precipitation
Heavy Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Temperatures remained unseasonably warm with the "Pineapple Express" Flow sending Heavy PI rates driven by WSW to SW Winds in the Moderate Range with Gusts into the Stong Range. Wind Blown and or Transport was Moderate.
Snow Characteristics
New Snow Depth
12"
New Snow Density
Medium
Snow Surface Conditions
Dense Loose
Wind Crust
Damp
Snow Characteristics Comments

The Brighton Area received at least one foot of new snow from 0600 to 2100. Storm Totals from the past two days are now close to 20 inches with at least 2.5 inches of water. The snow in the Brighton area was dense and slab like with significant amounts of graupel. In Silverfork at 8000 feet Storm Totals are 13 inches with similar water; and the snow at 8000 feet was mostly Heavy and saturated.

Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
Poor Snowpack Structure continues to be present in the upper pack as a result of the cold dry weather earlier in the the week. As noted by the other observers, Basal Facets in steep upper elevation Northerly terrain are still suspect. Rapid loading from both Wind and Heavy moisture laden Snowfall have created Soft Slab Avalanche activity, both Natural and Human Triggered. Cracking was Widespread along with the Avalanche Cycle that was observed in most areas within the Brighton Perimeter.
Avalanche Problem #1
Problem
New Snow
Trend
Increasing Danger
Problem #1 Comments

The Widespread Avalanche Cycle was mostly confined to the New Snow and the reactive layer was at the interface of the new snow that began around 0600 on Saturday morning. Heavy Precip has continued through 2200 hours, and up stream moisture appears to be in place for continued snowfall through the evening hours.

Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Same
Problem #2 Comments

On Saturday, the winds were very active out of the SW and W Loading leeward aspects and crossloading terrain features. It appears that these winds have died down slightly by 2200, and in areas where these winds remain more benign, these Slabs may still be sensitive yet more stubborn on Sunday. The overall trend may be decreasing Slightly on Sunday if these winds continue to decrease.

The Third Avalanche Problem continues to be Persistent and Deep Slab, depending on the location and depth. With two Persistent Weak Layer Slabs Avalanches reported on Saturday, and considering the poor visibility, there may have been others. Basal Facets have been observed in many locations in the upper elevation northerly facing terrain that was housing early season remnants of snow.

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