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Observation: Brighton Perimeter

Observation Date
1/3/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter: Mary Chutes, Claytons Peak, Lacawaxan, Hidden Canyon, 10420
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Significant Overnight Snowfall appeared to become Very Light by 0600. No signficant accumulations during the day. Winds accelerated out of the WSW around 1130, and were in the Moderate Speed Range. Wind Blown and or Transport was on the High end of the Moderate Range with Cornices continuing to build and Active Loading occurring. Temperatures remained in the teens throughout the day. Skies became Broken by the end of the day.
Snow Characteristics
New Snow Depth
19"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments

Excellent Riding on all aspects with the Leeward NW, N, and NE aspects having bottomless "Blower" Powder. Wind Crusts/Slabs of up to 24 inches were observed from Cross Loading.

Many people stated this was the Best Day of the Year!

Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Poor Snowpack Structure relating to the PreStorm Weak Surface Snow did not appear to be reactive despite the new Load. With the aforementioned increasing WSW Winds and Loading during the Mid Afternoon Wind Slabs appeared to be growing on the NE aspect off of 10420. MInimal Soft Slab development was observed on Claytons, yet there were no Red Flags observed in this location. Cracking in Cross Loaded Wind Slabs on the 10420 Ridgeline were up to 24 inches in depth and releasing on test slopes. Heavy Overnight Snowfall appeared to not have gained Slab integrity due to the lack of Winds and Ultra Light Density Snowfall that occurred during the afternoon on the 2nd through the early morning hours on the 3rd.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments

See above, and the Moderate Mid Day Winds appeared to have briefly Increased the potential for this Problem. As of 1700 hours, Ridgetop Winds continue to have speeds capable of Significant Transport and associated Loading on N, NE, and E upper elevation aspects. Due to these continual Winds, the Danger for this Problem appears to be Increasing with the abundant Light Density Snow available for Transport.

Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #2 Comments

Widespread PreStorm Weak Surface Snow Conditions may have allowed for poor bonding in some locations where these Facets were not destroyed by PreFrontal Winds; and as the New Snow from the latest event settles into a more Cohesive Slab this Problem may become more Sensitive and Reactive.

There were no concerns observed today for this Problem, yet due to the Widespread Nature of it before the latest event, it is not possible to rule it out. And as well, the significant recent Load combined with Strong Upper Elevation Winds may be enough to reactivate the Basal Facet Concerns on Very Steep Upper Elevation NW, N and NE Facing terrain,similar to the terrain affected in the White Pine Incident.

Problem #3: Storm Slab: Sluffing in the New Snow was Observed today and there was an apparent Storm Slab Weakness 12 cm down. This Problem should not be as active on Wednesday, yet Very Steep Slopes may continue to exhibit Loose Snow Dry Avalanche Potential.

Despite no Avalanche Activity observed today in this location, the aformentioned Winds appear to require the possibility for Naturals in Steep NE facing Upper Elevation Wind Loaded Terrain, and as a result the Danger for Tuesday was Considerable. With sustained Winds and the forecast for a possible additional 12 to 15 inches of New Snow, the Danger Rating for Wednesday appears to remain Considerable.

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