Observation: Willows

Observation Date
12/11/2016
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Willows
Location Name or Route
Willow Heights, West Willow, Mule Hollow
Weather
Sky
Overcast
Wind Direction
Southwest
Wind Speed
Light
Weather Comments
Skies were Overcast until early afternoon and then became Broken with enough sun to create crusts on SSE, S and SW. Tempertures remained in the mid to lower 20's for the same early day period and then rose accordingly. Winds out of the SW to WSW in the Light Range with no signs of Transport observed.
Snow Characteristics
New Snow Depth
5"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

Since 1700 on the 10th another 5 inches of Light to Moderate Density snow fell. Riding conditions were excellent on Moderate and Low Angle terrain with Southerly facing slope riding well until after noon when the sun became a factor. Trail breakiing was still thick in many places. Below 8400 feet yesterday warm temperatures and precip caused saturated wet snow to be buried by the last 5 inches that fell late on the 10th into the early morning hours on the 11th. Regardless even these wet grains allowed for supportable excellent riding. M/F crusts will be found on SSE, S and SW aspects on Monday the 12th. Wind scouring observed even at some WSW and SW mid elevations slopes that generally are protected terrain. As well, scouring observed on many ridgelines with the same aspects.

Red Flags
Red Flags
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
New snow that fell in the Lower Elevations were experiencing rapid warming concerns in the afternoon hours. Poor Snowpack Structure continues to be an issue of concern with the latest round of mid pack and basal facets that were reactive with the new load from earlier in the weekend. Of note: no Natural activity observed today in areas traveled. Wind Slabs investigated as well as the reactive Storm Snow that were issues on Saturday appeared to have settled out significantly with the cold overnight temperatures.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments

Deep Slab issues continue to be the Wild Card with the rapid loading from the latest event. Though nothing was observed in the small area traveled today, combined with poor visibility during the times traveled may have limited observing this possibility in other Upper Elevation Northerly facing terrain.

Avalanche Problem #2
Problem
Wet Snow
Trend
Decreasing Danger
Problem #2 Comments

Lower elevation Wet Loose activity in the afternoon hours was limited and predictable.

Danger observed in area traveled was Moderate today, and it appears that with the Persistent and Deep Slab issues a possibility, it will remain Considerable in Upper Elevation Northerly facing terrain due to the possibility of continual Wind Loading. Mid pack facets not noted today in areas traveled and this will be another possible concern until ruled out over the next two days. .

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