Turnagain Pass Avalanche Forecast

A remotely triggered avalanche was reported in Girdwood Valley in the Notch Mtn area around 2,500′ on a SW aspect. The avalanche was witnessed by another group in the area. It was ~3′ deep and unknown how wide or far it ran due the view being obscured.

Otherwise, that last known avalanche was a natural avalanche cycle that occurred during heavy snowfall and strong winds early on New Year’s and morning.

The active weather continues. Starting around midnight, snowfall intensity picked up (above 1,000′, rain below) and winds have really picked up. As of 6am 8-12″ of new snow has fallen at Turnagain Pass, 4-8″ in Girdwood Valley, and 3-4″ at Summit Lake. Easterly ridgetop winds have been 30-40mph with gusts as high as 74mph on Max’s Mtn. Both precipitation intensity and winds should be on the decline through the day. However, avalanches will still be prime for people to trigger in the new storm snow. Remember, watching for any recent avalanche activity will be a good place to start when evaluating our Red Flags (recent avalanches, cracking or collapsing in the snow, heavy snowfall and strong winds).

Wind slab avalanches are likely to be found and triggered on slopes that have seen, or are still seeing, active wind loading. Depending on how good the visibility is today, it could be hard to see these signs of wind loading. Be sure to always feel for stiffer snow over softer snow and any cracks that shoot out from you.

Along ridgelines, cornices could be teetering on the brink of failure. They have grown significantly since the holiday storms and could look much different. This is something to watch for as the skies clear and it’s much easier to travel along ridges.

Shallow soft slab avalanches, composed of the new snow, could be an issue anywhere over 8″ of snow falls. Stick your hand in the snow now and then to see how much new snow has fallen. If you are in area that got over 8″ of snow overnight, that new snow may not have bonded yet to the old surface and could slide easily.

Moderate winds along the lower Sunburst Ridge were taking minutes to fill tracks back in. Stronger winds were noted at the higher elevations. 1.3.23.

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Buried under this morning’s storm snow, the New Year’s snow, and the Xmas snow, are various layers of weaker faceted snow. These are the December facets that formed mid-December, and the facets surrounding the Thanksgiving crust. They are anywhere from 3-5′ deep. Could one of these layers be responsible for the Notch Mtn avalanche? Possibly. We’ll try and find out. For now, we all need to be aware there could be larger avalanches under just the storm snow issues. Another reason to be extra cautious.

As more snow falls, these layers are getting deeper and deeper and are also become more compressed. These two things really help them adjust and heal. It also begins the transition into a Deep Persistent Slab problem in the event they are not completely healed – something we are currently evaluating.

Snowpit tests at this site produced no signs of reactive buried weak layers. However, this area sees a lot of traffic. As skies clear and travel to other areas becomes easier, weak layers could turn out to be more reactive. 1.3.23.