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Observation: West Willow

Observation Date
2/7/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Willows » West Willow
Location Name or Route
West Willow/Mule Hollow
Weather
Sky
Overcast
Precipitation
Moderate Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
S2 Snowfall throughout the morning hours up until 1100, then clearing with Broken Skies. Snow was moderate to heavy in water content. Wet would be the best way to describe the weather with high humidity. Southwest winds up until noon were not getting down into the mid elevation protected terrain, but by early afternoon and at 2000 hours the SW winds were Strong with Intense gusts even in areas that are generally quiet. Transport and or wind blown was moderate to strong at times on the exposed ridgelines. Temperatures at 8000 feet remained in the upper 30's throughout the day and at 2000 hours they were registering 39 degrees.
Snow Characteristics
New Snow Depth
8"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Damp
Snow Characteristics Comments

Dense, spring like powder that rode very well and fast on low angle terrain was found above 8500 feet. Below this the snow was damp by 0800 and got progressively wetter throughout the day. Wind scour was observed on the exposed W through S aspects in the upper elevations. The snow was not inverted in this location as reported by others.

Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
The main Red Flag of the day appeared to be Wind Loading and this was widespread in the upper mid and highest elevations. Heavy Snowfall in the morning hours resulted in easy shears in the upper density breaks in the new snow, but later in the day these settled out quickly. Avalanches as reported by White and others appeared to be possible in many other locations, but none were observed in this area traveled.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Same
Problem #1 Comments

Wind Slabs may be stubborn and more prevalent in mid slope areas, as well as cross loaded mid slope terrain features due to the high wind speeds observed. At 2000 hours the winds remain Strong and this Problem may remain active on Wednesday.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

The warm temperatures and Rain that is misting and falling at 2000 hours may help keep the Wet Loose issues active on Wednesday. Roller balls and point releases were observed in many locations by mid day.

Cornice Fall issues appear to be very Likely over the next 48 hours at least. With mid spring like daytime highs in the forecast all normal spring problems will Likely remain active.

Persistent Slab issues continue to be possible and Likely in isolated terrain areas outside the Cottonwoods at mid elevations due to buried Surface Hoar. Of note: the NSF's that were reactive two weeks ago in the same location in West Willow, NE facing, were non-reactive today and difficult to even identify with snow pit and hand shear tests.

With the forecast winds and unseasonably warm temperatures Natural activity appears to remain possible. Danger for today appeared to be Considerable due to these concerns, and it appears Likely that it will remain Considerable on Wednesday.

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