Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2
Many steep slopes remain suspect and one can still trigger an avalanche on - or on approach to - recently wind drifted slopes holding older sugary faceted grains. While a slab exists now in part due to the recent winds, in general it lacks great structure and connectivity currently to break out wider than - say 100' or so. Thursday's storm may provide that.
Still, the current snow structure and avalanche type will allow you to tiptoe into steep terrain and then release well above you. This is what makes these avalanches unmanageable and why yesterday very experienced skiers and guides agreed that safe "available terrain has narrowed significantly in the last 48hours".
Guide/educator Cody Hughes's take on the snowpack below.
Problem: Nearly all aspects and elevations held very weak faceted sugar snow before the storm. The dangerous slopes will be the ones where winds have drifted snow into a cohesive slab. Unfortunately, many of the tell-tale signs of drifts (rounded, chalky, etc) will be covered and hidden by the new low density snow.
Solution: Slope angle is the key. Stay off of and out from underneath slopes 35° and steeper. See UAC forecaster Toby Weed's video below.
Polemic on Wind
Winds drift snow with little equity in regards to distribution on both a macro and micro scale. Southwest winds (from Sunday night) often favor northwest to east facing slopes...but drifts can often be found on nearly any aspect due to terrain channelling. Beyond that, winds from this direction typically pummel areas on the south side of Little Cottonwood Canyon (Maybird, Red and White Pine, etc), upper Big Cottonwood and the south end of the Park City ridgeline. More wind=more danger.
