Adventurous scramblers who peek into a steep avalanche gully in the Hoback Canyon might think they’ve been transported to Naboo, the home planet of “Star Wars” droid R2-D2.

Gazing into the Cow of the Woods slide path, an adventurer would spy a robot eerily similar to, but much larger than, the fictional movie character. The real-life Hoback Canyon robot doesn’t contain the schematics to the Death Star battle station or a distress call from Princess Leia, but it is a lifesaving droid nevertheless.

The sole job of the Hoback droid is to spark a gas explosion to provoke snow avalanches when the Wyoming Department of Transportation wants them to slide. The state agency first closes U.S. Highway 191 between Bondurant and Hoback Junction. Workers then employ the remote, robotic exploder when no cars or people are in the danger zone below the avalanche chute.

WYDOT operates a handful of remotely operated avalanche exploders above two highways in Teton County. They create explosions after a mixture of gas and oxygen is ignited in a large tube or cone. The force is directed toward the snow and causes it to slide.

But the first exploders WYDOT installed — on Mount Glory above Highway 22 between Wilson and Victor, Idaho — require upkeep. A supply building nearby is stocked with gas and oxygen before winter begins. Because they are permanent, large, culvert-type devices, they have to be serviced where they were built.

“They blow up,” said Jamie Yount, WYDOT avalanche technician. “It’s a hard life. It all takes maintenance. You need to be up there.”

Winter maintenance on Mount Glory — the destination of countless backcountry skiers — is one thing. But no one skis near or around the steep, cliff-framed Cow of the Woods slide path.

Enter R2-D2, officially known as an O’Bellx exploder. It is an aluminum cone with gas storage and electronics. The O’Bellx can be hoisted by helicopter to an avalanche-resistant pedestal constructed in the summer in the slide starting zone. An airship picks up the O’Bellx on a tether, flies it to the pedestal and deposits it there where it is secured automatically.

The O’Bellx contains a salvo of hydrogen and oxygen that can be spewed and ignited from a safe position on the highway. It was invented by TAS, a European company specializing in the control of natural hazards.

“If I need to bring it down and put more gas in it, I can just hire a helicopter,” Yount said. Maintenance can also be done at a site of WYDOT’s choosing, not up in the cliffs.

WYDOT installed the first O’Bellx in North America — at Cow of the Woods — in the fall of 2013. It installed its second, also in Hoback Canyon, at the Calf of the Woods slide path in 2015.

Before the O’Bellx, WYDOT would bring down slides with artillery or by dropping hand charges from a helicopter. The artillery shot was a difficult one, however, requiring a high-angle trajectory into a hidden starting zone.

“It’s challenging to get the rounds in there,” Yount said. “We are going to phase out of artillery in one more year.”

The four permanent Gazex exploders on Mount Glory use propane and oxygen. The first was installed in 1992. WYDOT has two other remotely operated devices that protect Teton Pass — North American Avalanche Guard systems that lob 9-pound charges onto the slopes.

The Gazex exploders cost on the order of $50,000 each. Installation would add another $100,000 to the cost of each if contracted out. WYDOT did that work itself. A single O’Bellx costs approximately $145,000. WYDOT put up the Hoback array for about $325,000, Yount said. The payoff comes in the reduction of highway closures.

Using the department’s Howitzer, closure times in the Hoback Canyon averaged 77 minutes. With the O’Bellx, the average closure time is 26 minutes.

“We’ve gone down to the Hoback and done avalanche control in seven minutes,” Yount said. “I think it’s a worthy investment.”

“It’s ingenious,” WYDOT commissioner Bruce McCormack said of the technology. Fellow commissioner Todd Seaton is similarly impressed. WYDOT no longer has to wait for nature to act first. “In an hour or two in the middle of the night, we’ll take care of it,” he said.

Angus M. Thuermer Jr. is the natural resources reporter for WyoFile. He is a veteran Wyoming reporter and editor with more than 35 years of experience. Visit for the full version of this story.

Angus M. Thuermer Jr. is the natural resources reporter for WyoFile. He is a veteran Wyoming reporter and editor with more than 35 years experience in Wyoming.

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