Observation: South Hollow

Observation Date
3/5/2013
Observer Name
Weed, McAvoy
Region
Logan
Location Name or Route
Providence Canyon-South Hollow
Weather
Sky
Clear
Wind Direction
Southwest
Wind Speed
Light
Weather Comments
Nice mild day, with intense midday solar warm-up.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Snow Characteristics Comments

Lots of graupel within the new snow. Only a few inches of fresh snow capping Friday's rime-crust. Best powder conditions in the deep trees.

Red Flags
Red Flags
Cracking
Collapsing
Rapid Warming
Red Flags Comments
We noted some localized cracking of the new snow around us up high as we flexed the rime-crust with body weight. I triggered a whumpf in a low angled meadow at around 8200'. It was our second visit to the spot and I was tapping snow off my ski with my pole when it occurred. There are a couple thin sugary weak layers made up of faceted snow within the upper couple feet of the snowpack in this area.
Avalanche Problem #1
Problem
New Snow
Trend
Increasing Danger
Problem #1 Comments

The whumpf I triggered is enough evidence for me that persistent slabs are possible.... The warming temperatures, wind drifting, fresh snow and rain at lower elevations could increase the danger in outlying areas.

There are many areas in the Logan Zone with shallow and weak snow and resulting poor snow structure, and I distrust steep slopes where I suspect this to be the case.

Avalanche Problem #2
Problem
Wet Snow
Problem #2 Comments

We triggered a small moist sluff entraining the few inches of fresh snow on an east facing slope... This one was quite manageable, but judging by the snow in the sun, other shallow point-release activity was likely on most sunny slopes with a few inches of fresh snow.

MINI BLOG: "Heat Related" would be a better term than "wet" describing the problems brought about by rapid warming of a still winter snowpack plagued by faceted snow. Of most concern to me are Persistent or Deep Slabs made more likely by increased creep rates in the upper layers of the snowpack, moistening of persistent weak layers consisting of faceted snow, and perhaps radiation and/or heat-caused softening of existing hard slabs.