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Observation: Snowbird periphery

Observation Date
4/17/2018
Observer Name
B
Region
Salt Lake » Little Cottonwood Canyon » Snowbird periphery
Location Name or Route
Snowbird Periphery
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
North
Wind Speed
Moderate
Weather Comments
Temperatures remained unseasonably cold throughout the day. Winds were variable out of the NW and N, and were in the moderate category in the upper elevations. Transport was moderate to strong at times. Snowfall was intermittent with periods of S3.
Snow Characteristics
New Snow Depth
14"
New Snow Density
Low
Snow Surface Conditions
Powder
Melt-Freeze Crust
Snow Characteristics Comments

The new snow overnight was light density and by 0800 was 5 inches with another 9 during the daytime hours. The new snow was slightly inverted due to the mixed grains and graupel that fell at times. Low and moderate angled terrain rode slow due to the inverted snow, and you could feel the scratchy pre-storm m/f crusts on the steeper terrain. The vast majority of the W and NW facing upper elevation terrain had areas that were wind swept and or scoured.

Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Poor Snowpack Structure
Red Flags Comments
Numerous weaknesses within the new snow were observed and validated by snow pit tests. CTH SP scores indicated a faceted graupel layer buried 54 cm down, at the interface to the previous storm from the end of last week. Widespread cracking and easy shears with slope cuts were found either one inch up from the new snow/old snow surface, and or right at the old snow surface on the stout m/f crusts. Intense wind loading was observed on the highest exposed ridgelines. Rates of S4 were observed around 1400. Natural wind aided storm slab avalanches were observed E and NE facing terrain at mid and upper elevations.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments

See above

Avalanche Problem #2
Problem
Wind Drifted Snow
Problem #2 Comments

See above.

Isolated areas considerable were occurring with the natural activity, but the majority of the terrain had a moderate danger.

Rapid warming and intense April solar will likely ramp the danger rating up to considerable during the daytime heating on Wednesday.

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