BOISE, Idaho -- The jumpers leaping from the Perrine Bridge in Twin Falls free-fall for three seconds before releasing their parachutes during a 486-foot descent.
The bridge is the only manmade location in the United States where so-called BASE jumpers -- short for the buildings, antennae, spans and earth from which participants leap -- aren't required to get a special permit for year-round jumps.
It also was the scene of four accidents in as many days last month, including one that killed a 34-year-old California woman. Still, officials say they don't have any plans to increase local regulation of the sport.
"We spend more time out on lost snowmobilers than we ever do on BASE jumping," said Nancy Howell, spokeswoman for the Twin Falls County Sheriff's Department. "We're not reassessing anything."
Unlike skydiving, where people jumping out of an airplane have several thousand feet to pull their parachutes, the margin for error in BASE jumping is much narrower. Once they jump, they have only a few seconds to deploy parachutes packed specially to fill with air quickly.
Shannon Carmel Dean of Alameda, Calif., became the third person to die since 2002 while jumping from the Perrine Bridge when she slammed into the Snake River on May 29 after her parachute failed to deploy.
Since 1981, there have been at least 99 BASE-jump fatalities around the world, according to the World BASE Fatality List, a Web site maintained by a BASE jumper.
Those risks haven't kept about 1,500 BASE jumpers around the world from making an estimated 40,000 jumps annually, said Martin Tilley, owner of Asylum Designs, an Auburn, Calif., company that makes equipment for BASE jumping.
"BASE jumping is never going to go away," he said. "You're never going to eliminate the desire for people to thrust themselves off fixed objects and float safely to earth with the aid of a parachute."
In Twin Falls, jumping already has resumed since Dean's death, said Tom Aiello, a BASE-jumping instructor.
"I wouldn't exactly say it's business as usual," Aiello said. "But things go on."
Twin Falls officials have quietly encouraged BASE jumping since it began there in the 1980s, in part because the estimated 5,000 jumps each year bring cash into the local economy.
But in most of the United States, jumpers often face arrest. The National Park Service doesn't permit BASE jumping, including from the monoliths of Yosemite National Park, where six people had died, including a woman who was protesting the ban. An 876-foot bridge over West Virginia's New River Gorge is open just once a year.
BASE jumping has been forbidden for years on 730-foot Foresthill Bridge in Auburn, Calif., where a stuntman in the Vin Diesel movie "XXX" used a stolen Corvette to start a memorable BASE jump. (The film crew had a permit. Diesel's character gets arrested.)
An estimated 50 people jump each year anyway. Park managers issue about three $250 citations annually.
"One guy bungee jumped, and as he got up to the top, he cut himself loose, and BASE jumped down," said Mike Lynch, the area's supervising ranger. "He was cited. Or as we like to say, given his 'certification' on the jump."
Officials are considering requests to loosen the restrictions. But Lynch said nothing is decided, and the existing ban will likely remain.
A new draft of National Park Service management policies released in October had proposed striking the provision banning BASE jumping. The final version is due out later this year, but officials in Washington, D.C., say it would still be up to park superintendents whether to issue permits. So far, no park officials have expressed interest in doing so.
"It would probably take a lot of courage for superintendents to propose allowing BASE jumping because it has had such a difficult history in the parks," said Chick Fagan, deputy chief in the NPS's office of policy.
Although leaping from bridges and other easily accessible sites is largely forbidden, jumpers can spring freely from remote cliffs on Bureau of Land Management territory, including hundreds of sites in the Utah desert.
Unlike the National Park Service, BLM officials say their mission is to promote "multiple use" of public land, including cattle grazing, hunting and BASE jumping. They do, however, encourage etiquette to reduce conflicts with others on the land.
"We don't like people to jump into campgrounds," said Maggie Wyatt, BLM field manager in Moab, Utah. "It tends to alarm the campers."
Marta Empinotti-Pouchert, 41, who teaches BASE jumping to experienced skydivers in Moab, was in Twin Falls the day Dean died.
"It's always devastating," Empinotti-Pouchert said. "But as a jumper, you think, 'What's the option?' To live not fully? To be afraid of living? Because people like us -- we need this."