Turnagain Pass

The Turnagain, Girdwood and Placer zones have entered the “Normal Caution” regime of backcountry hazards. What this means is triggering an avalanche is unlikely but not impossible. Watch for south facing slopes to become wet and punchy by the afternoon and keep in mind the following:

• Wet loose avalanches – Unusually warm air associated with a high pressure system is upon us. Temperatures along ridge tops are at or above freezing. Sun and daily warming will allow lower elevation temperatures to rise into 30s F and possibly 40s F at ridge tops. In this case, triggering wet sluff will be possible if the slope is steep enough. Most southerly slopes have already gone through several melt-freeze cycles, but should surface snow become wet natural wet-loose activity is not out of the question, especially under rocky terrain.
• Outlier slab avalanches – It’s unlikely but not out of the question that a person could trigger an old wind slab in steep terrain, all aspects – shaded or sunny.
• Cornice falls – Cornices that are baking in the sunshine can become weaker and more unstable. Give these features lots of space if you’re traveling along a ridge
• Glide avalanches – It’s always best to limit exposure under glide cracks. Please let us know if you see a glide crack release into an avalanche. The last known glide avalanche was on Goat Mt. in the Girdwood Valley 9 days ago.

Today will be the 7th day of sunny and springtime weather. The warmest day so far was Monday 2/25 and today looks similar. Several wet loose avalanches were seen on South facing steep rocky slopes, like this photo of a mountain near Portage Valley. Keep close tabs on how the snow surface is heating up during the day.

Surface crust on steep Southern aspects is 1cm to 1″ thick. If this crust becomes wet and saturated avoid steep South aspects. 

South of Turnagain – Summit Lake/Silvertip/Johnson Pass zones: A shallow snowpack with a generally poor snowpack structure exists in these areas. A variety of weak layers sit in the mid and base of the snowpack and were re-activated last Thursday by the outflow wind event. Many natural avalanches were seen on windloaded slopes in the Summit Lake area. Although whumpfing has been observed in the Summit area, no signs of instability may be encountered before a slab is triggered.

Again a quick recap of the weak layers sitting in the pack:

Valentine’s Layer: Small facets, 10″-16″ deep, last avalanches on 2/21 due to wind event region-wide. Not showing signs of reactivity in Turnagain/Girdwood/Placer currently. Layer was responsible for the 2/19 snowboarder remotely triggered slab on Seattle Ridge.
MLK Jr Layer: Buried surface hoar, 2-3′ deep, last avalanches seen in this layer 2/21 in the Summit Lake region. All natural slides.
Basal facets (large faceted snow near the ground): This layer has only been found in the Summit Lake region and produced at least one very large natural avalanche on Thursday, 2/21.
If you’re headed this way, remember the snowpack becomes more complex – evaluate terrain exposure and the snowpack as you travel.