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Observation: Mill B South

Observation Date
3/25/2019
Observer Name
Grainger, Young, Olafsen
Region
Salt Lake » Big Cottonwood Canyon » Mill B South
Location Name or Route
Mill B South
Weather
Wind Direction
South
Wind Speed
Light
Weather Comments
Forecasted warming occurred in basins while light wind kept ridgelines cooler than I expected. Winds increased slightly around 1500.
Red Flags
Red Flags
Recent Avalanches
Cracking
Collapsing
Rapid Warming
Red Flags Comments
A rather productive natural cycle occurred yesterday morning due to graupel and high PI rates. These storm slab releases were prevalent in Cardiff and Mill B South today, particularly under alpine rock bands and cornice on the leeward slopes (N half of the compass). As the storm produced early yesterday these natural and ski-triggered releases easily failed on the frontal graupel layer and with a hard crust as a running surface widely propagated as soft slabs. This was the scenario in the Cardiac Bowl incident yesterday and the crown was still mostly apparent, hugging the bottom of the cliff band across much of the bowl. Mill B South showed similar widespread results, 7-14" slabs under rock bands, D1-D2 terrain dependent.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments
Today this slab was less sensitive but slightly more cohesive due to wind/time. Still easily triggered with skis on steep lee slopes. This was helpful in safe travel and our group was able to manage terrain with ski cuts in appropriate starting zones.
Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments
Didn't witness any storm slab turn release as wet slabs but very widespread roller balls on all thermal slopes. High east faces started wet loose activity ~1000 hrs and it followed around the S half of the compass through the day.
Comments
Easily ski-triggered remaining storm slabs aided travel in appropriate start zones.
1-2mm Graupel healing but lingering sensitivity where present.
N-facing terrain like this had widespread natural activity.
Natural and ski-triggered slab pieces helped create travel options.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Moderate
Coordinates