Avalanche
Things are a bit touchy in Idaho right now.Â
On Sunday, March, 17, an avalanche forecaster triggered a destructive wet slab avalanche near Dollarhide Summit in the Smoky Mountains of Idaho by throwing a snowball at a slope. It ran 1,400′ to the valley below. A forecaster discussion on the Sawtooth Avalanche Center’s website shared information about the current wet slab avalanche cycle running in both the Smokey Mountains and Sawtooth Range of Idaho:
“That afternoon, I watched 3 wet slab avalanches run naturally from the top of Galena Peak. While these events were in zones with shallower snowpacks, the potential for these same slides to run the Sawtooths zone remains. Meltwater percolating through the snowpack is weakening the bonds at buried persistent weak layers. When this happens, wet slab avalanches are on the menu. These are most likely during the heat of the day and into the late afternoon, but the timing of these types of slides is unpredictable. Even slopes with a refrozen crust at the surface are suspect when water is moving through the snowpack. Natural avalanche activity can also continue long after the heat of the day.” – Sawtooth Avalanche CenterÂ
Smaller wet loose slides can trigger much larger wet slides as they travel downslope. If someone triggers one of these slides it will be nearly impossible to ski or ride out of. These have the potential to run full track, depositing deep piles of debris on the valley bottom.
Forecast Discussion for the Smoky Mountains
Yesterday was warm, wet, weird, and wild out in the mountains. Today will be warmer, wetter, weirder, and wilder. Expect wet snow problems to be larger, more dangerous, and more unpredictable today than yesterday. Even on colder slopes, you still can’t write off triggering a persistent slab avalanche on buried weak layers. Does this sound hard to navigate? It is.
The snowpack starts with a crust today, and will break down quickly. After this, wet loose avalanches can start anywhere where the snow is moist and mushy. Hard to predict wet slab avalanches can break on slopes even where surfaces still have a crust, as meltwater from past days percolates through the snowpack to weaken bonds between buried weak layers. Wet loose slides can start at a point, gain speed and mass as they move downhill, and then flank out to create these large and destructive wet slab slides. All of this will be happening naturally. If you head to colder, drier aspects to avoid wet snow issues, you’ll still find a persistent slab problem.
Overlapping complex problems, as well as the hard-to-predict nature of both wet slab and persistent slab problems makes for a tricky day to travel in the mountains. You’ve made it this far in the season, you’ve been patiently navigating persistent slab and new snow issues. Things will continue to get more dangerous as we continue into our warmup. Hold onto that patience just a bit longer, and make conservative travel choices. Today is the day to start early, end early, stay off of and out from under steep slopes, and mostly just stay out of the way.
