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Observation: East Mineral

Observation Date
2/27/2021
Observer Name
Greg Gagne/Anna Marno/Troy Tully
Region
Salt Lake » Big Cottonwood Canyon » Mineral Fork » East Mineral
Location Name or Route
Mineral Fork / East Mineral
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Generally light winds at our elevations (< 9200'). Occasional periods of heavy S2 snowfall with some graupel.
Snow Characteristics
New Snow Depth
14"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
30-40 cms storm snow. HS ranges from 130 cms to 2 meters.
Red Flags
Red Flags
Heavy Snowfall
Cracking
Poor Snowpack Structure
Red Flags Comments
During periods of heavy PI, we were getting cracking in the storm snow as well as noticing stress cracks in the surface on steeper rollovers. We did get one collapse at 8,200' on a E/SE aspect.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments
New snow was sensitive during periods of heavy PI, and shovel tilt tests were getting some Q2 shears at new/old snow interface. Storm snow instabilities likely have settled out by Sunday morning.
Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #2 Comments
I have been in to Mineral five times this season, and overall it has a thinner/weaker snowpack than the upper Cottonwoods. However, there is now a ~1.5+ meter slab on top of the faceted snow down near the ground. It is still easy to identify the facets at the ground with a probe, but on one pit at 8,200' on an E/SE aspect, the facets are gaining strength.
Need more data, but perhaps we are beginning to turn the corner with our PWL layer as the facets gain strength and the slab on top strengthens and increases in size.
We still avoided slopes steeper than 32° today where the faceted layer is present (north half of the compass), and spent virtually all day on slopes < 30°.
Comments
Probably the best pit we've seen this year! ECTN4 at the new snow/old snow interface (down 30 cms). The facets down near the ground are also gaining strength. Pits I have dug on this same aspect/elevation in Mineral this year have had very weak snow down near the ground, so this is a positive sign. (But we need much more data than this one pit.)
With clearing late in the day, views across into alpine terrain in Mill B, upper Mineral, and west-facing Kessler were showing no natural avalanches at all.
Saw some evidence of cross-loading on a mid-elevation slope from the NW winds, with obvious wind drifts on leeward aspects.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable