Turnagain Pass

A few shallow wind slabs were triggered yesterday in Girdwood Valley’s Notch area. These were reported to be fresh wind slabs on the windloaded sides of rollovers in the trees. Report HERE.

Fresh wind slab skier triggered in upper Girdwood Valley (Notch area) yesterday. Thank you to Kakiko Ramos-Leon for the photo. 2.18.23.

After a long stretch of unsettled weather and poor(ish) visibility, what looks to be a nice sunny Sunday is on tap. Several inches of low density snow fell yesterday, with what looks to be an average of 4-6″ in most places. The winds over the past couple days have been moderate to strong from the east and enough to form wind slabs in some areas. With this, plus sunshine today and a few questionable buried weak layers, there are a lot of avalanche issues we should be on the lookout for if headed out.

Wind Slabs:  Lingering wind slabs, similar to the photo above, may still be triggered today. Although these are likely getting more stubborn with time, there could be some that are still touchy if they happen to be sitting on one of the various layers of buried surface hoar that have sprouted up over last week. Watch for cracking in the snow around you and stiffer snow over softer snow. These are expected to be in the foot deep range and found in the usual places along ridgelines, on rollovers, and in cross-loaded gullies. They could be a bit concealed by a skiff of new snow that fell after the winds.

SUN EFFECT:  The sun could be strong enough today to warm and initiate sluffs in southerly steep rocky terrain. These could start small, but with several inches of loose snow on the surface they could run further and gain more volume than one may expect.

Loose snow avalanches:  Watch your sluff. Just like that stated above, sluffs could be larger than expected and likely easy to trigger on steep slopes.

Cornices:  With weather conducive to ridgeline travel, be sure to give cornices a wide berth.

Although we have seen many areas with a generally stable snowpack, especially around Turnagain, there are still some questionable layers in the top 3 feet. A skier found one of these layers reactive in the Girdwood Valley (Crow Creek, Goat Shoulder) two days ago. At elevations between 1,000 and 2,000′ roughly a buried crust from Jan 25 exists that in places has weak facets above it. It seems that the thinner snowpack areas, where this layer is ~2′ deep or less, still has spots it is reactive. These areas are Crow Ck drainage and the southern end of Turnagain Pass toward Johnson Pass.

Additionally, over the past 10 days three layers of surface hoar grew in brief spells of clear skies that are now intermixed in the top foot(ish) of low density snow. These layers don’t seem to be causing much problem now, but the last known layer that formed on Feb 15, which sits around 6-10″ deep, seems like it could be more of an issue. Something to keep in mind moving forward. Quick hand pits to see if there are any easy shears, watching for cracking in the snow around us, and jumping on small test slopes, will be tools for sussing out any funny business under the soft surface snow.

This is a photo of an Extended Column Test (ECT) that broke in an old layer of buried surface hoar but did not propagate. It’s a good sign when these tests do not propagate. Thanks to Blase Reardon (Director of the Flathead Avalanche Center in Montana) for the photo and test results. 2.18.23.

Avalanche legend Nancy Pfeiffer came out to look at the avalanche that was skier triggered on Friday up Crow Creek. We found the slab (14-16″ deep) to have released on facets over the 1/25 crust. 2.18.23.

In areas with a thin snowpack (i.e, Silvertip and the southern end of the forecast region to Summit Lake) there are various weak layers near the base of the snowpack that remain a concern. For these areas, triggering a larger avalanche is not totally out of the question and a more cautious mindset is recommended.