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Observation: Monitors

Observation Date
12/23/2019
Observer Name
Champion
Region
Salt Lake » Park City Ridgeline » Monitors
Location Name or Route
Willow Knob - South Monitor Bowl
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Precipitation began approx noon. Snow started warm, wet and light. Throughout the tour, it was on and off, by 4 pm the snowfall rate had increased, temperatures had dropped, and it was coming in as a mixture of precipitation particles and graupel. Winds were light to moderate throughout the day, moving snow and sustained at ridgelines.
Snow Characteristics
New Snow Depth
1"
New Snow Density
Medium
Snow Surface Conditions
Dense Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments
A lot of snow characteristics out there today. All wind effected terrain had obvious signs of the high winds yesterday and sustained winds today. Growing cornices, wind drifted snow, thin wind skins, and wind slabs could be found at many mid and upper elevations. Areas in the trees that stayed protected from the high winds and mid and lower elevations still had some dense loose snow.
By the end of the tour 4 cm of new snow mixed with graupel had fallen on wind crusts, solar crusts, and damp old snow.
Red Flags
Red Flags
Wind Loading
Poor Snowpack Structure
Comments
The riding conditions took a beating yesterday with the winds, and snow was still being transported.
Visibility was poor, but we went and looked at the South Monitor bowl avalanche. After yesterday's winds, the crown had been filled in, but dirt and trees in the path were still visible leading us to believe this avalanche ran in the weak old snow. Adjacent to the South Monitor Bowl avalanche we stuck our shovels in and were able to find the same poor snowpack structure we have been discussing for the last month. We found 25 cm of weak, sugary facets below a thick slab. At 9800' on a North aspect, the height of snow was 165cm deep. There was about 4cm of graupel on top of a 140cm slab from 4F-P hardness. This was all sitting on top of 25cm of 2-4mm facets and depth hoar. These facets still possess scary characteristics, and while the likely hood of triggering them is low the consequence is high.
With sustained winds and obvious signs of transportation, the slab on top of these weak facets will just continue to grow. Triggering a soft or a hard slab of wind drifted snow holds the potential to pull out into this still present persistent weak layer.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate