Avalanche: Moonlight

Observer Name
L. Dunn
Observation Date
Wednesday, December 25, 2019
Avalanche Date
Wednesday, December 25, 2019
Region
Salt Lake » Big Cottonwood Canyon » Mineral Fork » Moonlight
Location Name or Route
Mineral Fork/Moonlight
Elevation
9,500'
Aspect
Northeast
Slope Angle
Unknown
Trigger
Natural
Avalanche Type
Soft Slab
Avalanche Problem
New Snow
Depth
12"
Width
300'
Vertical
300'
Comments
A 300 foot wide avalanche seems to have broken out near the end of the heavy snow that fell Tuesday night into Wednesday morning. There was only an inch or two of new snow on the debris, so the avalanche likely occurred near dawn Wednesday morning. The crow was approximately one foot in height and there was about 14" of new snow in the area, so the avalanche was only in the new snow. As you can see in the attached image, the crown was in steep terrain in the lee of a terrain feature where wind loaded snow would have likely accumulated during the wind event from the previous weekend. We did not go and investigate the crown or the bed surface. The debris ran up to 300 vertical feet from the crown down onto the top part of the Moonlight run where people typically de-skin and ski. The debris was very soft and light.