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Observation: Big Cottonwood Canyon

Observation Date
3/19/2018
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Mid BCC, and Upper BCC
Weather
Sky
Broken
Wind Direction
West
Wind Speed
Light
Weather Comments
Light west winds with no transport observed. Temperatures were very cold in the early morning hours and rose rapidly by late morning. Highs in mid canyon between 8000 and 7000 were in the mid 30's with the upper elevations appearing to remain below the freezing mark throughout the day. Despite the cooler temperatures at the upper elevations the intense mid March solar makes things feel much warmer. Skies began totally clear and by mid day they filled i with cloud cover, and at 1800 they are overcast.
Snow Characteristics
New Snow Depth
3"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

Another day of superb powder riding. By 1015 hours The east and SE were becoming damp and this process continued around the lower half of the compass throughout the day. Tuesday will see m/f crusts on all aspects on the lower half of the compass. Minimal wind damage from the last 24 hours was observed, and only isolated small pockets of soft wind slabs were encountered.

New snow again overnight added another 3 inches of very light density snow as a cap to the storm snow from over the weekend. Bottomless riding and foot penetrations of up to at least 24 inches were observed on the northerly aspects above 9600 feet.

Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Red Flags Comments
The biggest Red Flag observed were the loose snow dry and wet avalanches. Loose snow dry avalanches/sluffs were easily triggered on slopes with angles > 35 degrees and for the most part they were manageble. One group of riders descending the west facing steep terrain off of Millicent triggered a sluff and eventually entrained enough snow to build up close to a meter of debris before stopping. Numerouns loose dry natural avalanches were observed on west and northerly facing steep slopes, and in one location a sluff stepped down and broke out a very small pocket of storm slab that appeared to be 8 to 10 inches deep. Roller balls became widespread on the the south facing Highway to Heaven my mid afternoon, and in the mid canyon area widespread small wet loose avalanching was occuring on steep southerly facing slopes.
Avalanche Problem #1
Problem
New Snow
Trend
Same
Problem #1 Comments

Loose dry and loose wet as described above.

Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #2 Comments

The small pocket os wind slab encountered were 4 finger hard, up to 9 inches thick, and reactive to slope cuts. They appeared to be crossed loaded in some upper entrances to steep chutes leading into the Brighton Back Bowls. Their reactivity appeared to be as a result of a weak layer of light density stellars. In more exposed terrain in the alpine this problem may have been a bit more widespread.

Small sensitive cornices on east facing ridges in the mid canyon area were sensitive and easily triggered, yet they were not creating avalanches upon descent.

Danger today appeared to be an isolated moderate for wind slabs, loose dry, and loose wet. Many steep lines were ridden with only the loose dry issue as a concern.

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