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Observation: Figure 8 Hill

Observation Date
2/18/2017
Observer Name
Hardesty
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter » Figure 8 Hill
Location Name or Route
Alta/Brighton periphery
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
South
Wind Speed
Moderate
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Melt-Freeze Crust
Snow Characteristics Comments

A few inches of new on soft settled powder on northerlies...with dust on crust for the off aspects. Open and exposed terrain had the few inches of new over a 2" wind crust.

Red Flags
Red Flags
Wind Loading
Cracking
Red Flags Comments
Isolated cracking within new snow down 3 to 5" deep; some minor sluffing noted on steepest slopes.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments

Hunkered down in more wind protected terrain but noted drifting along higher ridgelines.

Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments

Storm plus potentially "persistent slab" -


Cracking and shear tests elicited weakness 4-6" down within the new snow just above the couple-day-old wind slab/crusts. These crusts in turn sit above last week's high pressure facets and - at least where I traveled - didn't have enough of a new load to step beneath the crusts in the faceted snow - perhaps at higher locations with more wind. I do think these would have been possible in this higher more open terrain, producing larger (still size 1.5) avalanches; and potentially triggered from a distance.

Snow Profile
Aspect
Northeast
Elevation
9,800'
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate