Turnagain Pass

There were no reported avalanches yesterday. However, over the weekend there were three human triggered avalanches with people caught and able to escape. Two of them (Tincan’s Library and Girdwood’s Raggedtop) were in our forecast zone and one just to the west in Falls Creek pictured below. The two avalanches in our forecast area were suspected to be wind slabs sitting on the weak snow from January. The Falls Creek avalanche appears to be settled storm snow sitting on weak snow from January. The common factor is the weak sugary (faceted) snow that formed during the January dry spell. More on that in Problem 2. A big thank you to all these folks for writing in and we’re grateful everyone is ok!

Skier triggered avalanche in Falls Creek from Sunday. Although this area is just to the west of our forecast zone in Chugach State Park, it is the type of avalanche we are concerned about in the Turnagain Pass area as well. Photo credit Mike Records, 2.4.24.

Clearing skies and a break in weather is expected today before another weak weather front moves in tomorrow. That front should bring clouds and 1-2″ of snow at best. Yesterday’s weather system was a bit more blow than snow. Around 1-3″ of snow fell in Girdwood, Placer, and Portage Valleys and just a trace at Turnagain Pass. The winds on the other hand were 10-15 mph and gusting near 40 from the east. Hence, another round of wind slabs were created yesterday. 

Wind Slab Avalanches:  On slopes in the higher elevations, or any exposed slope in the mid elevations, watch for signs of prior wind loading. There have been several wind events now and a variety of wind effected snow exists. Cracking in the snow around you, hollow feeling snow, and stiffer snow over softer snow are clues to look for. Watch for wind slabs to be cross loaded in gullies mid-slope and not just at the top of slopes. These slabs have the potential to break larger than expected due to the weak snow underneath from January.

Triggering what may seem like a surprise avalanche is possible on any slope steep enough to slide. That is because of a suspect weak layer anywhere from 10-20″ below the surface. This is the old surface from the January dry spell that is now a buried layer of sugary faceted snow. The layer is quite variable as to how weak it is and is something we are sussing out. The slab on top of it is also quite variable. Slopes with wind loading are clearly an issue as we’ve already seen avalanches, but areas without are also concerning. The warming temperatures can make this setup more reactive as well as the wind loading. Looking ahead, any new snow that slowly accumulates can also make this setup more worrisome. All that said, there is a lot of uncertainty as to how many slopes could produce an avalanche today and into the future. Watch closely for signs of instability (cracking and whumpfing).

Lower Elevations: I went over to Placer Valley yesterday to see what the lower elevation terrain looked like and found very weak facets under 12-16″ of settling soft snow (video below). For those headed to these areas, be suspect of steep slopes at these lower elevations as well as the higher elevations. Please keep us posted on what you find out there, good or bad.

Snowpit at the lower elevations in Placer Valley area. The weak sugary facets are pretty easy to spot in this pit.

Glide avalanches are still a concern on any slope with glide cracks present. We have not seen or heard of one releasing into an avalanche for over a week now, but that doesn’t mean one can’t pop off today. Continuing to avoid any time under these is prudent.