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. What to keep in mind in the backcountry today:

• Wet sluffs on steep south facing slopes – watch for snow on steep south facing slopes to become wet and punchy by the afternoon. In this case, triggering a wet sluff will be possible if the slope is steep enough. Most southerly slopes have already gone through several melt-freeze cycles and natural wet loose activity is not expected today. 
• Outlier slab avalanches – It’s unlikely but not out of the question that 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. We need to continue giving these a wide margin. 
• 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 8 days ago. 

Today will be the 6th day of sunny and springtime weather; sunglasses have entered back into the morning checklist. The warmest day so far was Monday 2/25. Several wet loose avalanches were seen on steep rocky slopes. A few slabs popped out on Monday as well under rock bands triggered by wet loose debris. These slabs, seen in the photo below, were likely composed of the 10-16″ of settled storm snow from 2/16-2/20. Today is not expected to be as warm as Monday but tomorrow has a chance. Keep close tabs on how the snow surface is heating up during the day. It is springtime and time to consider travel routes for late in the day. 

Steep rocky southerly facing slopes are feeling the springtime sun and warm ambient air temperatures. Many wet loose avalanches released Monday afternoon 2/25 during the warmest day seen this season (this one pictured is from Crow Ck drainage).

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. 

Natural avalanche on Fresno Pk from last Thursday, 2/21. This slide was triggered by significant wind loading from the outflow wind event. It broke in weak layers deeper in the snowpack.