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Observation: Porter Fork

Observation Date
12/6/2018
Observer Name
Greg Gagne and Tom Flaherty
Region
Salt Lake » Mill Creek Canyon » Porter Fork
Location Name or Route
Main Porter Fork
Snow Characteristics
Snow Surface Conditions
Dense Loose
Wind Crust
Snow Characteristics Comments
Whereas earlier this week the snow surface was weakening under cold, clear skies, today it was much denser and not as loose as 48 hours ago; most likely due to warm temperatures and cloud cover. Did also notice settlement cones (see photo below). HS now 90-100 cms > 8000' in Millcreek. Some wind effect also noted.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
No collapsing.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
Did find some of the weakest basal facets I've seen in the central Wasatch. Mostly looking at west and northwest aspects > 8,000'.
Comments
I was interested in looking at snowpack in Millcreek after seeing Peter Earle's observation of a likely remotely-triggered slide in Porter Fork on Sunday. Main Porter is steep-sided, and the steep gully where this slide is located is shaded (photo). But I was also finding weak snow down near the ground on northwest and west aspects from 8200' and above. The slab above the facets continues to strengthen, and is now 4F to 1F in hardness.
Settlement cones around trees and shrubs are an indication of the low-density snow from this past week settling and the slab gaining strength.
Video discussion of what we found on northwest aspect at 9400' in Millcreek.
Video
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable