Observation Date
1/1/2020
Observer Name
Gagne/Duvernay
Region
Salt Lake » Big Cottonwood Canyon » Butler Fork
Location Name or Route
Butler Basin - Wilson/Soldier
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Direction
Southwest
Wind Speed
Strong
Weather Comments
Winds picked up in the afternoon with some very strong gusts getting well down into drainages. It did not snow for most of the tour, but around 3 pm snowfall picked up with graupel.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
About 10 cm (4") new in mid-BCC. Wind drifts along the ridges were mostly 10-15 cms (4-6"), although some drifts were up to 40 cms (16"). These were generally on leeward north and east aspects from the southerly/westerly winds.
Red Flags
Red Flags
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Getting some cracking in fresh wind drifts along ridges. Poor snowpack structure refers to old snow surface which was a combination of very weak stellars with some near-surface facets.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments
Not enough new snow to create a storm slab, but widespread wind drifts on north and east leeward aspects primarily along ridgelines were sensitive.
Video below shows snowfall as well as one of the stronger gusts along the BCC/MCC ridgeline between Wilson and Soldier.
Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments
Although there was only 10 cms/4" new snow, additional snowfall overnight will create sensitive storm slabs during the day on Thursday.
Comments
Was especially interested today in seeing how reactive the old snow surface was to the new snow and fresh wind drifts. Overall there wasn't enough of a storm slab on top of the old snow surface to get it reactive, but the bond was poor to the old snow surface which consisted of loose, weak stellars. Video below describes this interface, and how it may become reactive with additional snow and wind.
Video
Hazard today was Moderate on wind-loaded slopes where we were traveling. Likely Considerable by Thursday morning with additional snow and wind.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Considerable
