Observation: Park City Ridgeline

Observation Date
2/27/2013
Observer Name
American Avalanche Institute Level 2 - Konigsberg
Region
Salt Lake
Location Name or Route
Bear Trap, Mill D North, PC Ridgeline
Weather
Sky
Clear
Weather Comments
Only significant weather to speak of was strong solar. Temps topped out at about 18F at 9000ft but felt much warmer with strong late Feb sun.
Snow Characteristics
Snow Surface Conditions
Powder
Melt-Freeze Crust
Snow Characteristics Comments
Solar aspects held cold snow this morning if you got to it before the sun. All solar aspects will be crusted tomorrow as we noticed on our late afternoon exit on an easterly facing slope. Northerly aspects low density snow with no wind effect in areas traveled. Surface hoar noted on all aspects this morning but will only be preserved on shady aspects.
Red Flags
Red Flags
Collapsing
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
One group noted a few collapses on east facing PC ridgeline. In moonrocks area (north of squaretop) a skier triggered a slab that moved slightly but the slab arrested and did not release. Structure still has a lot to be desired around the PC area. Worst structure found on SE facing slopes... multiple crust facet sandwiches and shallow snowpack... but no slab so not really a red flag at the moment.
Avalanche Problem #1
Problem
Wind Drifted Snow
Problem #1 Comments
Main concern was small layer of facets above and below MF crust below latest storm snow on all aspects except N and NE. Hard to see with the naked eye but confirmed with magnification. Felt this may well be the cause of recent avalanches on south facing aspects in LCC and not new snow/old snow interface. This layer fails CTM but showing low propagation propensity with ECT. For our area we did not find any evidence of wind slabs so not a concern for us. Wet activity was minimal today (noted a few size 1 wet loose in the afternoon south of Ivory Flakes in Cardiff). Overall strength is moderate to strong, structure is fair with areas of poor (see red flags), and propagation propensity is moderate (tests say low but collapses trump test scores.) Layer of most concern is .5mm facets above MFcr. Bottom line, although we have a few weak layers to watch in areas travelled, the present slab or lack of slab is not overloading any weak layers. Overall stability rated as good.