Turnagain Pass

We have not received any reports of new avalanche activity.

It’s been an unusual week of weather, with mostly clear skies, unseasonably warm temperatures, and very strong sustained east winds for 5 days. The winds are expected to gradually decrease today as the weather pattern shifts and some light precipitation and cloud cover move into the area. The most likely avalanche to encounter today is a wind slab, which you could find anywhere from treeline up to alpine elevations. Due to the sustained strong winds, it is possible that wind slabs could be firmer and larger than typical. Human triggered and natural wind slab avalanches are likely and could be anywhere from 1-2+’ deep. Keep an eye out for wind slabs in areas with active wind loading – like along ridgelines, gullies, and convex features. You can identify wind slabs by looking for hollow feeling snow or shooting cracks and using small test slopes to see if they are reactive to the weight of a skier.

Wet loose avalanches are also possible today, especially below 1500′ where the warm temperatures and rain showers expected today could melt the icy surface crust. These tend to occur on steep slopes and are typically not large enough to bury a person but can grow in size if they run far down slope and entrain more snow on the way down.

Sustained strong east winds with clear skies are not a typical weather pattern for us. Graphic 2.17.24

Wind transport down to treeline elevations on Sunburst, with lots of snow blowing off ridgelines. Photo 2.15.24

A layer of faceted snow buried 1-3′ deep in the snowpack which formed during the January cold spell has been causing a lot of large avalanches this week, including the avalanche fatality on John Mtn in the Summit Lake area. This persistent weak layer is a little bit less concerning in Turnagain Pass compared to Summit Lake, but human triggered avalanches are still possible. This type of weak layer is concerning because it can cause very large avalanches and release on uncommon terrain features like in sheltered areas at low elevations. Avalanches can also be triggered remotely with this type of weak layer, which means you can trigger an avalanche from low angle terrain which releases on adjacent steeper slopes. In parts of the Turnagain forecast area with a typically shallower snowpack, like Silvertip, Lynx Creek, or Crow Creek, this layer may be weaker and act more similarly to Summit Lake.

The best way to stay safe during periods with an active persistent weak layer is to stick to lower angle terrain and be aware of runout areas from overhead avalanche paths. Persistent weak layers can be tricky to assess in the field because they often do not provide any obvious signs of instability, like red flags, before causing an avalanche. Digging a snowpit to identify the weak layer in the snowpack and test it using a stability test is a good way to track the weak layer in the area you are travelling. Often snowpit tests can give inconclusive or false stable results on persistent weak layers, so we recommend using them as a tool to get more information about the snowpack structure but not making a decision to go into avalanche terrain based on the results of snow pit tests. It is important to be patient during periods of persistent avalanche problems and give the snowpack time to heal.