Observation: Green Slope

Observation Date
3/14/2019
Observer Name
Evelyn and Trent
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter » Green Slope
Location Name or Route
Green Slope
Weather
Sky
Broken
Weather Comments
Mostly cloudy and thin clouds, but by mid afternoon, the sun breaks were becoming more frequent.
Snow Characteristics
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
Powder in the morning, but surface snow rapidly becoming damp in the afternoon with even short breaks in the clouds allowing sun to hit the slopes. Snow just starting to become thick. Slopes that caught sun will be crusted tomorrow, but there will be plenty of cold powder left early tomorrow. Tomorrow is THE morning to get an early start - I'd expect the snow to heat fast once the sun hits the slopes.
Crust beneath the new snow was felt mid-slope and below on the sunny slopes, even on low angle slopes. New snow was deep enough at the upper elevation not to feel the crust on the upper elevation, southerly facing slopes.
Red Flags
Red Flags
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
Rapid warming is the number one issue for tomorrow with the forecast for clear skies and warming temperatures. I expect the cold, new snow to be very reactive to the sun and heating, with wet loose sluffs becoming easy to trigger, and natural avalanches occurring. Super early starts advised, plan an exit without being on or below steep, sunny slopes or in steep low elevation terrain on all aspects.
Comments
Sun crust beneath the new snow was the most interesting layering. Widespread on the southerly aspects we traveled, all the way to the 10,200' ridge line.
I was very interested to get full propagation above the crust on one of the Extended Column Tests. I think the crust can play into tomorrow avalanche activity in a couple of ways. First, as a good bed surface, allowing wet loose sluffs to run far. Second, it will faciliate slab avalanches in places, or wet sluffs transitioning to slabs as the snow runs down slope.
Cornices are huge...keep well back from the edge.
Today's Observed Danger Rating
None
Tomorrows Estimated Danger Rating
Considerable