Turnagain Pass

With partly cloudy skies expected again today along with light northwest winds and very cold temperatures, the snowpack continues to stabilize. During this process, the surface is becoming weaker and weaker by the day as that fluffy snow from Monday turns into faceted ‘recycled powder‘. This greatly reduces any chance for a slab avalanche, but in turn increases the volume and speed of loose snow sluffs. We’ve had a few folks report sluffs that are gaining volume, taking the top layer of snow and running all the way to the bottom of the slope. Although very unlikely, the weight of a large sluff could overload an old stubborn wind slab from early January hidden under Monday’s snow- creating a larger avalanche. In general, If headed to the steeps, don’t underestimate the sluff. This is a very predictable issue and one that falls in the Normal Caution regime of low avalanche danger. The other issue that is on our minds are the northwest winds.

Wind Slab avalanches:  The northwest outflow winds over Southcentral Alaska have been ushering down Cook Inlet and for the most part, have spared the Turnagain Pass area. With such loose snow on the surface, it won’t take much wind to create a hair-trigger wind slab. With that said, keep a close eye out for areas with any wind effect and slopes with wind loading. Feel for stiffer snow over softer snow and look for smooth pillowed drifts. This issue is mainly outside of our forecast zone, but as wind can do weird things, we need to be on the lookout for wind effect in any area we travel.

Locations suspect for wind slabs:  Summit Lake, Johnson Pass, Bench Peak and all the way south to Seward. The Seward area saw significant wind over the past two days with some natural avalanche activity. Portage Valley and the Whittier areas. North of Girdwood in the Crow Pass region.

The animation below from windy.com shows the general forecast wind pattern along ridgetops, around 5,000′ in elevation. Blue is light wind and orange/red is strong (color legend is on the bottom of the image). Note: weather model data is useful for a general pattern and not always accurate for a specific point. It also becomes less accurate the further out in time.

Cornices and Glide Cracks:  As always, limit exposure under glide cracks and give cornices a wide margin.

Old avalanche activity from the 1/20 storm along with the corniced ridgeline on Magnum’s SW face at Turnagain Pass. Also barely seen is a small glide crack slowly opening. 1.24.20. Photo: Billy Finley