BASE Jumpers Look to Court for Chance to Take Flight in Yosemite

If you were to hike to the top of Yosemite National Park’s iconic Half Dome and toss a rock off the sheer cliff face that rises thousands and thousands of feet above the valley floor, it would fall for about 14 seconds.

For extreme-sport athletes who hurl themselves from cliffs and buildings with specialized parachutes, the rock toss is an old school method for gauging the height of a jump. And 14 seconds is more than enough time to deploy a parachute, take control, and land.

Nestled in California’s glacier-carved Sierra Nevada mountains, Yosemite is packed full of similarly tall rock faces and spires unlike anywhere else in the country. The cliff’s are vertical, the granite rock beneath a jumper’s feet won’t crumble, and Yosemite Valley features large flat meadows for soft landings.

There’s no place quite like Yosemite in the eyes of a BASE jumper: The sport was invented there in the 1970s, attracting thrill seekers who use parachutes or “wingsuits” with underarm panels reminiscent of a flying squirrel that return them to earth from tall structures.

But for close to a half century now, no one has been allowed to jump in the park. Not legally.

The National Park Service has strictly enforced a regulation known as the aerial delivery rule that prohibits using a parachute to land on federal park land.

Now, the extreme athletes are trying to change the law through litigation, combining wonky and evolving questions about the regulatory power of America’s federal agencies with a niche daredevil sport.

In February, the nonprofit BASE Access sued the National Park Service in federal court, alleging the agency is violating the US Constitution by criminalizing an activity without citing any federal statute that explicitly bans BASE jumping. A hearing is scheduled next month.

The NPS argues that it is well within its authority to create rules regulating recreational activity in the park. Without that power, the agency argues, it wouldn’t be able to restrict any number of harmful activities, like dumping trash in the parks or cutting down trees.

But lawyers for BASE jumpers have turned to the legal theories behind the Supreme Court’s 2024 Loper Bright decision that limited federal agency power. For BASE jumpers who’ve long wanted to leap from Half Dome, this lawsuit may represent the best chance they’ve ever had of flying in Yosemite without fearing arrest.

“There are people who’ve retired from jumping who are in their 70s, but if Yosemite became legal, they’d get a rig again,” said Brendan Weinstein, an avid BASE jumper and the president of BASE Access. “It’s pretty much a dreamland for BASE jumping.”

Bad Blood

Almost every year, park rangers arrest BASE jumpers who continue to flock to Yosemite. They’re charged with federal misdemeanors in the small federal courthouse inside Yosemite Valley that stick on their record permanently. Some have gone to jail for days. Others face thousands of dollars in fines and are put on federal probation.

For decades rangers and jumpers have engaged in a dangerous game of cat and mouse. Fearing they’ll be spotted by rangers, jumpers will fly early in the morning or at dusk, in low light conditions that only increase danger.

Modern BASE jumping was born in 1978 when cinematographer and skydiver Carl Boenish jumped from the top of the 3,000 foot rock formation El Capitan in Yosemite Valley with a specialized parachute. BASE stands for buildings, antennas, spans, and earth—a reference to the types of “exits” that jumpers can launch themselves from.

As the sport grew in popularity, the NPS worked out a trial program in 1980 that required prospective jumpers to apply for permits that let them hike to the top of El Capitan and jump in the early morning.

But the relationship between rangers and jumpers quickly began to sour, partially the result of a large group of jumpers who drove a flatbed truck through the Yosemite backcountry to get closer to the top of El Capitan and jumped without permits during the trial period. They’re known in the BASE jumping community as the “Flatbed 10.” The park ended the permit program after only two months, citing the disruptions, and no one has been allowed to legally jump in Yosemite since.

Some jumpers believe the bad blood stems from the animus of Bill Wendt, Yosemite’s chief ranger in the 1980s. Former park ranger Carol Moses, who served from 1974 to 1992 wrote in a sworn affidavit for a pending Yosemite criminal case against a jumper that Wendt frequently espoused his dislike of BASE jumpers. Moses said the park rangers formed a patrol tasked with arresting BASE jumpers, known as Stop Parachutists Leap At The Top, or SPLATT.

That mentality among park leaders appeared to stick. “It transitioned from leaders in the NPS to subsequent leaders in the NPS over decades,” said Matt Gerdes, a BASE jumper and author of The Great Book of BASE, widely regarded as the Bible for BASE jumping technique. “I don’t know exactly why that culture still exists, and I also am not sure how much better it’s getting.”

A spokesperson for the NPS declined to comment for this story, citing the agency’s policy to not discuss litigation.

The NPS’ aerial delivery rule that it uses to prosecute jumpers dates to before the sport was invented. Congress in 1916 created the National Park System Organic Act, which gave the agency broad authority to create park rules and regulations “necessary or proper for the use and management” of park land.

In the 1960s, as the NPS sought to acquire private land across the American West for parks, the agency engaged in “heavy-handed” tactics with land owners, such as refusing to plow roads after heavy snow fall in an effort to get them to relinquish control, according to BASE Access’s lawsuit.

The NPS implemented the aerial delivery rule in 1965 as a way to regulate how these private land owners could get access to food and supplies through airplane drops. The rule that exists today, last updated in 1983, prohibits “delivering or retrieving a person or object by parachute, helicopter, or other airborne means, except in emergencies” or under the conditions of an NPS issued permit.

The agency has never issued permits to jump in any national park with the sole exception of New River Gorge in West Virginia. The park issues permits for a BASE jumping festival known as Bridge Day that occurs at a 900 foot bridge during a single day each year, an event that long predated the creation of the park in 2020.

A Path to the Courthouse

Weinstein started BASE jumping in 2014 after he saw a video of a wingsuit pilot flying high above a road in Norway. Wingsuit flying is an even more specialized form of BASE jumping that uses a suit with fabric between the arms and legs, allowing one to glide for long distances across the air before eventually deploying a parachute.

He’s since engaged in jumps around the world. BASE jumping is generally legal on land owned by the Bureau of Land Management and in Europe, where athletes flock to the cliffs in the Swiss Alps.

In 2021, Weinstein was visiting Yosemite—with no intention to BASE jump, he said—when a ranger detained him for having a suspicious looking bag. The ranger had seen a parachutest land a half hour earlier and was looking for the jumper.

The ranger let him go, but Weinstein later received a summons in the mail to appear in court for a citation. He realized he could get a federal misdemeanor on his record, and unlike state misdemeanors, federal records generally are permanent. He started calling around and found he wasn’t alone.

“I have 20 plus friends with permanent federal criminal records who are all otherwise law abiding, fantastic human beings,” he said.

Katie Hansen, a skydiver and BASE jumper who holds a number of skydiving world records, was arrested in the park in 2004 for a jump. She spent a night in jail and had to forfeit her BASE jumping rig. She was sentenced to three years of federal probation and had to pay a $1,500 fine, according to court documents.

More recently, BASE jumper David Nunn pled guilty to violating the aerial delivery rule after jumping from El Capitan in 2020, agreeing to 12 months of probation and a year-long ban from the park. Nunn had originally fought the charges, with his attorneys arguing that NPS’ underlying criminal regulation should be invalidated as “arbitrary and capricious.”

Magistrate Judge Helena Barch-Kuchta, who oversees the small Yosemite federal courthouse where BASE jumpers are charged, denied Nunn’s motion to dismiss the indictment last year.

Hansen didn’t respond to requests for an interview, and an attorney for Nunn didn’t respond to a request for comment.

Weinstein hired a defense attorney for his citation and the NPS ultimately dropped his case, but the incident continued to bug him. What law prohibits BASE jumping? He went down a rabbit hole of administrative law and congressional delegation authority.

Congress had never written a criminal statute that prohibits BASE jumping on national park land. The aerial delivery rule was the creation of the NPS, he discovered.

Through friends in the community, Weinstein, a software engineer, connected with fellow BASE jumper and skydiver Dylan Avatar who’d had some experience with government relations, and the two formed BASE Access in 2023. They connected with fellow jumper and attorney Kendrick Dane who became the group’s general counsel. BASE Access filed applications for permits to BASE jump in almost a dozen national parks and received rejection after rejection last year. Their appeals to the agency failed as well.

“At this point, I was listening to administrative law podcasts,” Weinstein said. He eventually connected with a law professor who put him in contact with legal advocacy groups that might be interested in taking their case pro bono.

BASE Access members called with attorneys at the New Civil Liberties Alliance, a libertarian Washington, DC, legal group that has emerged in recent years as a litigation powerhouse, taking a number of cases challenging agency power that have reached the US Supreme Court.

The group played a key role in the Loper Bright case and in convincing the high court to overturn the longstanding legal doctrine known as Chevron deference, which says that courts should defer to the expertise of federal agencies when interpreting vague congressional statutes. More recently, the group has challenged the Trump administration’s trade tariff plans on behalf of businesses.

The NCLA agreed to take the case, and in February it sued the NPS and the Department of the Interior, its parent agency, in federal court in Texas on behalf of BASE Access and a handful of jumpers. They’re asking for a ruling invalidating the aerial delivery rule as unconstitutional and allowing BASE jumpers back in the parks.

The case poses an important question about a long dormant administrative law issue known as the nondelegation doctrine, said litigation counsel Casey Norman. Is Congress allowed to delegate criminal lawmaking authority to the NPS without clear direction?

The doctrine says that Congress cannot delegate its power to executive branch agencies unless there is an “intelligible principle” that puts guardrails on the agency. The Supreme Court has largely shied away from weighing in directly on the doctrine or explicitly enforcing it over the past few decades, but it has signaled interest with its recent spat of rulings curtailing agency power.

The BASE jumper’s case presents a clear violation of the doctrine, Norman said, and the fact that NPS is creating criminal laws makes it all the worse.

“A lot of people are kind of skeptical, only because this involves BASE jumping, and they’re like, ‘Well, isn’t that like a crazy, foolhardy sport?’” Norman said. “It’s a question of if we want Congress to be doing its job, or do we want to let it just pass off the hard decisions.”

The NPS filed a motion to dismiss the suit in June with a hearing before the judge set for October. The agency argues that the 109-year-old National Park Service Organic Act is clear in delegating its authority to the agency and providing an intelligible principle of conserving the parks’ scenery and wildlife for the public’s enjoyment.

Eliminating the NPS’s ability to create regulations allows “any potentially harmful conduct, such as cutting down a giant sequoia in Yosemite, dumping trash into Old Faithful in Yellowstone, or defacing petroglyphs in Canyonlands,” the motion said.

A Dangerous Game

In the eyes of BASE jumpers, the cat and mouse game has only increased the danger of the sport.

In 2001, BASE jumper Frank Gambalie successfully jumped from El Capitan, but while fleeing from park rangers he entered the Merced River where he drowned. The famous Yosemite rock climber and BASE jumper Dean Potter died in a wingsuit accident in the park in 2015 when he impacted a ridgeline. He was jumping at dusk under low light conditions, and was flying a line requiring an updraft that’s best in the middle of the day, all factors which may have contributed to the accident.

Sneaking around with parachutes and looking out for rangers means jumpers aren’t focusing on the jump.

“BASE jumping is something that requires a lot of mental energy, a lot of physical performance, and when you start carving that up into other tasks, you’re taking away your ability to perform safely,” Gerdes said

There’s no doubt that BASE jumping is a dangerous sport, regardless of legality. Although the fatality statistics vary, one unofficial database says hundreds have died in accidents since 1981, and another study found the sport is 43 times more deadly than skydiving from an airplane. In the tight knit community, many BASE jumpers know someone who’s died doing the activity.

“Wingsuit BASE jumping is, by all accounts, the single most dangerous thing you could possibly do as human beings,” Gerdes said.

But when comparing recreation activities in the parks, BASE Access points to a selective focus on BASE jumping. NPS fatality data shows eight BASE jumpers have died in national parks between 2007 and 2024, according to BASE Access’ lawsuit. Almost 150 rock climbers and 23 skiers have died over that same period.

The lawsuit also points to the NPS’ decision to grant permits for hang gliding, a similar aerial sport where pilots launch from cliffs with large, fixed wing gliders.

For Weinstein, the BASE jumping ban is more than an issue of safety for thrill seeking jumpers and administrative law. It goes to the reason we protect wilderness, he believes, as a place where people can push their physical and mental limits far from the rest of society.

“If somebody wants to fly in Yosemite, they should be on top of Half Dome, they should be looking at the birds and going like, ‘Oh wow these birds are getting some lift over here, I want to go fly by those birds,’” Weinstein said.

“You shouldn’t be scanning, looking for rangers. You should be going, ‘This is beautiful, and I’m totally at peace.’”