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Observation: Park City Ridgeline

Observation Date
4/13/2017
Observer Name
B
Region
Salt Lake » Park City Ridgeline
Location Name or Route
Park City Ridgeline
Weather
Sky
Clear
Wind Direction
Southeast
Wind Speed
Moderate
Weather Comments
Clear skies throughout the day with a Few clouds moving in by 1500. High end Moderate SE wind velocities with Strong gusts were able to allow for Light Wind Blown and or Transport. Afternoon daytime highs were actually able to hit 50 degrees/plus at classically cool mountain locations.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

Overnight windy conditions and low RH values combined to allow for a minimal refreeze despite temperatures only dipping into the mid to upper 30's at upper elevations. The sustained winds observed throughout the day kept the upper elevation snow surfaces from getting too wet for much longer than anticipated. Overall snow surface conditions appeared to be in a transitional period as a result of the excessive warming today. In areas away from bushes, trees and rocks (and especially in open bowls) there was excellent supportable corn-like riding above 8800. SE through SW aspects had surface snow that were actually displaying 3 mm corn grains, and this was much different than observed a week ago in the same locations. The latest event from this last weekend has yet to fully cook down on the shady aspects at mid and upper elevations. Cold dry snow appeared to be limited to upper elevations at and above 9800 feet, and only on slopes with angles at or greater than 30 degrees. Challenging punchy/inconsistent riding was the rule below 8800 feet. Fortunately, the forecast for significant overnight lows for the next two nights should help promote a deeper refreeze, and Saturday looks like it will be a perfect day for harvesting quality corn.

Red Flags
Red Flags
Recent Avalanches
Wind Loading
Cracking
Rapid Warming
Red Flags Comments
Cracks were visible along exposed cornice lines on the Park City Ridge Line. Recent Loose Wet Avalanche activity was observed. See photos. Despite limited snow available for transport, Light Wind Blown was observed even at 9900 feet on the north aspects. See photo. In areas at higher elevations on similar aspects the possiblity for greater amounts of Wind Blown and Loading appeared very possible.
Avalanche Problem #1
Problem
Wet Snow
Trend
Decreasing Danger
Problem #1 Comments

During the transitional period from melt freeze crusts to damp, there was a brief period when isolated pockets of "Corn-Slab" collapsing were occurring. On steeper upper elevation slopes where this process was being delayed by the winds there appeared to be a potential for slab issues.

Otherwise, the excessive warming was definitely enough to help promote natural Wet Loose activity on the unconsolidated snow surfaces on the upper half of the compass as well as on the treed shady aspects as previously identified.

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

See photos and explanation above.

Foehn winds and excessively warm temperatures may have been enough to promote Cornice Failures later in the day.

Travel up until 1330 appeared to only have a Moderate Danger for Wet Avalanche potential, and very isolated pockets of small Wind Slabs. Travel later in the day may have seen the Danger escalate to Considerable with Naturals possible.

The approaching cold front forecast to hit the area Thursday evening should lock things up and the Danger for Friday may be back to Low again as the daytime highs for Friday look to be low enough to keep things mostly frozen.

Wet Loose Activity from South Monitor

Minimal/Light Wind Blown observed at 9900 feet, with the potential for greater amounts of Wind Blown at higher elevations on northerly aspects.

If you want the southerly aspects and faces to grow good corn, you need to stay off them when they are mushy!

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