Turnagain Pass Avalanche Forecast

With temperatures in the Alpine forecast to be in the single digits and low teens today, it seems like the arrival of spring is saying a big “April Fools’!” And instead of March coming in like a lion and going out like lamb, it’s more like most of the month has been the movie Groundhog Day. The weather forecast this morning is pretty similar to many of the days in March (and February). That being said, there is no reason to complain about cold soft snow sticking around on shady aspects. The only real sign of spring today is the sun crust on SW through SE slopes.

The main avalanche issue continues to be the possibility of triggering an avalanche on buried weak layers in the top 3′ of the snowpack. We know there are a couple of layers of buried facets and surface hoar across the forecast area. Snowpack tests have produce varied results, with some showing the potential for an avalanche to be triggered and some pointing towards stability. It has been a week since the last reported human triggered avalanche that failed on a buried weak layer. However, natural avalanches occurred in Summit Lake on Monday. Persistent weak layers in the snowpack often present this feeling of uncertainty and we aren’t ready to forget about them.  Steep terrain with wind loaded snow over the weak snow is the most suspect today. Be on the lookout for areas that were previously wind loaded and those with any new wind loading from the NW winds yesterday and today. Lurking slabs will likely be at upper and mid elevations, immediately below ridgelines, in cross-loaded gullies, and below convexities.

As always, use good travel protocol, and think about terrain consequences.   Hard wind affected surface snow might allow you to get well out on the slope before the avalanche releases and it might not be the first person that triggers the avalanche.

Wind Slabs: Observers yesterday reported a bit of snow moving with the northwest winds and if winds bump up today we could see more of that. Watch for pockets of fresh wind slab in upper elevation terrain. Look for shooting cracks and avoid hollow sounding snow in steep terrain. There is a blowing snow advisory for Whittier this morning.

Loose snow avalanches: Steep slopes that are sheltered from the wind have loose snow sitting on top of firm surfaces. It will be easy to trigger dry loose avalanches (sluffs) in that terrain today, and they can pick up enough volume and speed to carry a person. While it is unlikely they will be big enough to bury you, they can be dangerous if they drag you into terrain traps like cliffs, trees, rocks, or gullies.

Sun effect: Colder temperatures and NW winds should keep most surface snow from warming too much today. However, steep protected southerly slopes (especially under rocks) may get some warming from the afternoon sun. If crusts soften and/or you see any roller balls, move to a shadier aspect and colder snow.

Buried surface hoar in a snow pit on Tincan yesterday, 3.31.21. This same weak layer was reactive on Eddies on Tuesday but not on Tincan yesterday. This really illustrates the variability in the snowpack and the lingering possibility of finding the wrong spot and triggering an avalanche.