Observation Date
12/5/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Pioneer Ridge
Location Name or Route
Pioneer Ridge, Greenslope, Pioneer Bowl: Toilet Bowl Chute, V Tree, White Cliffs
Weather
Sky
Clear
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
NW winds were only detecible on the exposed upper elevation ridgelines and were in the high end of the Light Range. No transport and or wind blown observed. Temperatures did not appear to hit the expected forecast highs, and remained in the mid teens throughout the day. Despite this, temperatures in the direct sunshine appeared much warmer, with the shady aspects feeling like real winter.
Snow Characteristics
Snow Surface Conditions
Powder
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments
By 1000 hours SE aspects at 10200 with slope angles > 25 degrees were beginning to get damp. M/F crusts will now be found on SE, S and SW aspects that have slope angles > 25 degrees. HS in the upper 100 feet of Greenslope was very minimal, though once you got down lower in the slope the total snow was much deeper. Wind crusts and shallow snow resulting from scouring during the storm were observed on upper elevation exposed terrain features above 9800 feet.
Riding on the shady upper elevation aspects continues to offer excellent powder turning in up to 14 inches of light density with the buried rain crust keeping things supportable.
Settlement appeared to be minimal in this period just 12 hours after the latest event ended.
Red Flags
Red Flags
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
Significant warming today when compared to the previous day resulted in wet loose acitivity below 8000, and continual escalating daytime highs may bring about more of the same on Wednesday.
Poor snowpack structure throughout the snowpack on the shady aspects exists, and NCF's, recrystalized graupel, and depth hoar up to at least 14 inches are well established and in place. Note the photo which indicates significant graupel pooling as seen from pit taken at the top the riders left chute in the White Cliffs area in Pioneer Bowl. And, this 10 to 14 inch layer of graupel showed very little signs of cohesion with a fist plus hardness. Also of note was the fact that in this location the DH was fist plus and a bit more cohesive than pit and scores observed on the previous day near Catherines Basin.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments
Isolated pockets of wind slabs appeared to be more stubborn and less reactive. Despite this, the possibility of stumbling across terrain features that our housing wind slabs in steep upper elevation terrain still existed.
Avalanche Problem #2
Problem
Wet Snow
Trend
Decreasing Danger
Problem #2 Comments
Small wet loose avalanches were observed in the mid to lower elevations on steep southerly facing terrain features. Also, significant dry loose activity was easily triggered on northerly facing steep slope.
The previously cited poor snowpack structure may not be a problem currently due to the fact that the latest event only provided around an inch of water, but continued cold overnight lows and moderate afternoon temperatures will continue to help generate more metamorphic development and faceting throughout the snowpack. The rain crust was showing signs of breaking down in many locations, but is still evident; and the facet development above and below it continues to offer a potential initial weak layer of concern.
Note significant graupel pooling as indicated by the expanding and larger stripe of recrystallized graupel.. These areas in steep terrain under cliff bands will be suspect once the next load comes in either in the form of snowfall and or any increasing winds.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
