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Avalanche: Porter Fork

Observer Name
Grainger, Young, Dromgoole
Observation Date
Monday, February 28, 2022
Avalanche Date
Monday, February 28, 2022
Region
Salt Lake » Mill Creek Canyon » Porter Fork
Location Name or Route
Porter Fork
Elevation
9,500'
Aspect
Northeast
Slope Angle
38°
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Weak Layer
Weak Layer
Facets
Depth
14"
Width
60'
Comments
Multiple relatively harmless soft slab pockets in the upper Porter, Neff's and Thaynes drainages.
Some natural and some easily human-triggered, all are Class 1's in steep and rocky N through E facing terrain >8500'.
Failing on mid-February NSF's, these slides serve as an indicator for potential deeper slides with wider propagation once this weekend's storm adds water weight. Today's pieces were all soft, 8-15" deep and isolated to certain terrain features but with higher temperatures settling newer snow into more of a slab the shallowly-buried persistent weak layer may continue to produce slides on the firm underlying crust surface.
Most importantly, areas without previous disturbance (tracks, wind-texture, etc.) to that hard underlayer will be most reactive. A pretty complicated problem right now with a lack of continuity in aspect, elevation and areas throughout the central Wasatch.
Pics. 1&2- Natural in upper Main Porter, ~14" deep.
Pic. 3- Easy to trigger soft slabs on hard underlayer, failing on facets.
Solar aspects got warm today. Roller balls, pinwheels, shallow wet slabs and the distinct possibility of getting stranded overnight in the woods if you forgot skin wax.