You think you understand the snowpack? The mountains have a way of humbling even the most seasoned pros. The crew at Jackson Hole just dealt with a massive incident right next to the upper tram terminal on Rendezvous Mountain that should send a chill down every freerider's spine.
Here is the situation: A snowcat was working the tram dock, clearing snow. As it pushed a load off the edge, the entire slope ripped out. We aren't talking about a little sluff management here. This was a deep slab monster with a crown face averaging 8 feet deep, punching up to 10 feet in spots.
The Science of the Scare
What makes this terrifying is the timeline. The Jackson Hole Ski Patrol—who are some of the best in the business—had hammered this exact zone with two 30-pound bombs just the day before. The result? Nothing. The slope stayed put.
This is the nightmare scenario we call a Persistent Weak Layer (PWL). The slide ran on faceted crystals—rotten, sugary snow from October and November—buried deep at the base of the pack. These layers are notorious for being stubborn. They can bridge the weight of a skier or even an explosion, lurking until the stress hits a specific weak point or the load becomes just too much.
According to the report filed with the Bridger-Teton Avalanche Center, the weight of the snow pushed by the cat (and potentially the machine's vibration) provided the trigger that 60 pounds of high explosives couldn't. This is a classic "low probability, high consequence" event. The odds of triggering it were low, but the result was catastrophic.
Why It Matters
Jackson Hole is legendary for its steep terrain, earning a 67.2 on ShredIndex, but stats don't mean much when the snowpack is this complex. Early-season snow that sits around during dry spells turns into facets or depth hoar. When you stack a heavy winter snowpack on top of that house of cards, you get a structure that can support a lot of weight... until it doesn't.
The Bridger-Teton Avalanche Center has been flagging these persistent weak layers since Christmas. It’s a tricky beast to forecast because you can ski a slope ten times without issue, and the eleventh person (or a snowcat) hits the sweet spot and brings the whole mountain down.
The Takeaway
This incident is a heavy reminder that "controlled" terrain is managed, not manicured. If a 30-pound bomb can't wake the dragon, but a snowcat can, it highlights the uncertainty inherent in deep slab instabilities. The Tetons have had a busy, sketchy avalanche season, and this adds another layer of complexity.
Respect the closures, respect the patrol, and if you are venturing out of bounds, check your ego at the gate. The mountains are screaming right now; make sure you're listening.
Source: SnowBrains
