Selkirk Mountains

Following a period of record-breaking precipitation, we are left with more questions than answers about our snowpack. One thing we do know is that there are significant amounts of water saturating the snowpack from top to bottom. With the amount of moisture in the snow, different layers may weaken and break down, resulting in large avalanches. Give big open slopes a wide margin, and avoid travelling below steep terrain to account for the high degree of uncertainty.

Today, the atmospheric river that has been relentlessly dropping record breaking amounts of rain begins to loosen its grip on the Panhandle. Since December 9, rain totals across different SNOTEL sites in the Selkirks range from 1.9” to 4.9”, the Silver Valley-Bitterroots showing 2.9” to 4.4”, and the Cabinets receiving the highest totals with a whopping 2.7” to 8.7”. Because rain amounts to this magnitude far exceeds anything we have seen in recent memory, we have a lot of questions surrounding how exactly this is going to affect the snowpack and for how long.

Observations across all zones reveal that the rain and melt water have fully saturated the snowpack to ground at all elevations. Water is draining at the base of snowpack but is also pooling around different layers in the mid to upper snowpack. The good news is that all this free water is doing a great job of starting to eliminate the persistent weak layers, which is beneficial in the long run. The downside is that the water is now acting as a lubricant on these layers and is weakening the bonds between individual grains. So, we are transitioning from a persistent slab problem to a wet slab problem.

Since the rain reached all elevation bands and forecasting the exact timing of wet snow problems is difficult, any steep, open slope near tree line and above is susceptible to fail and should be given a wide safety margin. Avalanches could fail naturally or by human trigger. It’s going to take a prolonged period of below freezing temperatures to lock up the lower portion of the snowpack, and slopes with a surface crust may still be susceptible to triggering. Wet snow problems may not always present classic signs of instability, but sinking into wet snow to your boot top should be treated as a red flag, and warrants directing your travel plans to lower angle terrain.

Although it’s December, our snowpack looks and feels like it’s late spring. Glide cracks aren’t something we typically have on our radar near the winter solstice, but they are starting to pop up across the forecast area and more may appear in the coming days with warm temperatures. If you encounter a glide crack, stay far away from them and adjust your route so that it doesn’t cross below a crack. Glide avalanches can release at any moment without any warning signs.