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Observation: 10420

Observation Date
2/25/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
Mid BCC and 10420
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Direction
Southwest
Wind Speed
Light
Weather Comments
Early in the day the skies were broken and the winds were very light. By 1400 the clouds thickened and the skies became obscured, and the winds ramped up to the moderate category. Transport and or wind blown was moderate. At 1530 when exiting, wind slab development was insignificant at the mid ridge level of the 10420 west ridge. Temperatures never got out of the single digits at 9000 feet. Snow fall began around 1430 and by 1700 there was around 2 inches.
Snow Characteristics
New Snow Depth
2"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments

Both trail breaking and downhill riding was significantly improved from Friday. Significant sized settlement cones were observed, and conservative settlement estimates were at least 35%. As a result low angle riding was fun, and sluffing was not as reactive. Leeward slopes in the most exposed areas were much thiner with wind sculpting.

Red Flags
Red Flags
Wind Loading
Red Flags Comments
No avalanche activity observed again today. Yet, wih the winds ramping up in the afternoon it is highly likely that upper elevation ridges and terrain features were receiving loads that may have been close to tipping the scales.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #1 Comments

Forecast for pre frontal winds on Sunday appears to be enough to not only damage some of the terrain in the mid to upper elevations on the west side of the compass, but also promote more wind slab issues on the east side of the compass. E and SE aspects may be more dangerous due to the firm crusts underlying the latest round of precip.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

Cold overnight lows may prevent the same E and SE upper elevations aspects from receiving enough solar input to initiate Wet Loose activity, but if the sun continues to be out in the late morning and afternoon S through SW should see significant Wet Loose avalanching, especially on the steeper slopes.

Cornices continue to be a concern.

Sluffing on the very steep northerly facing terrain will also continue. Tilt tests continue to identify weak reactive snow 8 inches down with clean shears in a light density layer.

If the winds and or sun are able to promote natural avalanche cycle, then Sunday should see a danger rating of Considerable. Until then the danger for Saturday and into Sunday appear to be Moderate for Wind Slabs, Wet Loose and Dry Loose.

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