Turnagain Pass Avalanche Forecast

The primary concern today is a one-week old slab (1 – 3’ deep) sitting on a layer of buried surface hoar. Buried surface hoar has been found over the past week throughout Turnagain Pass and Summit Lake above 2000’ on all aspects. This particular combination of weak layer plus slab is known to linger for long periods of time and explains why we are still getting some moderate to hard results in our test pits when we isolate the weak layer. No new signs of obvious instability have been reported since the Sunburst avalanche that buried one skier on December 18th.  This leads us to believe that the weak layer is adjusting to its new load and the overall stability of the snowpack is gradually improving.

The weather forecast today is calling for 3-5″ of new snow throughout the day with moderate winds. This new load will contribute to our primary concern by placing additional stress on the weak layer. 

It’s important to realize a MODERATE rating refers mainly to the likelihood of initiating an avalanche and does not take consequences into consideration.  If you were to find just the right trigger point to initiate an avalanche it could propagate across the entire slope, making escape difficult at best.  Because of this we are on the higher risk side of the moderate scale. 

Persistent slabs are most likely to be triggered on steep slopes in thinner areas of the snowpack.  We are advising backcountry users to be smart about terrain choices and to think about the consequences before deciding to ski a steep slope. Take the time to evaluate the terrain and avoid steep slopes with convex rollovers or shallow areas around rocks.  

Ridgetop winds are expected to be moderate with gusts into the mid twenties today. We have an existing 5 inches of low density snow available for transport and are expected to recieve another 3-5″ throughout the day. This is just enough wind and snow to form isolated wind slabs up to 8″ deep on leeward aspects.  Terrain features such as ridges, gullies and convex rollovers will be the most likely places to encounter these newly formed pockets of slab. These slabs are expected to be small and isolated, but if caught off guard could be enough to knock you off your feet.  Pay attention to the consequences below and look for obvious signs like shooting cracks, hollow sounds, or smooth pillowy looking features.