Daredevil Nik Wallenda will walk across Niagara Falls tonight, but he’ll be attached to a tether just in case he loses his footing on the high wire. Still, some speculate that Wallenda could detach the tether mid-walk, leaving him at the mercy of the elements.

“It’s central to our agreement that he will have the harness connected, and we expect that’s going to be exactly what happens,” Jeffrey W. Schneider, senior vice president of ABC News, told the Buffalo News.

“I practiced with it today, and it is definitely a challenge,” Wallenda said in a CTV interview. “It’s very unique. It’s something I’m not used to, and I’m very uncomfortable with, but it is what it is.”

If the tether becomes caught on the wire, Wallenda does have the option of detaching it.

“I’m betting he takes it off,” said State Sen. George D. Maziarz told the Buffalo News.

If he does decide to unhook the tether, Wallenda must face the elements—and that wind and mist is no joke. And though he comes from a long line of successful daredevils, there’s no shortage of unfortunate instances in his family tree. Wallenda’s great-grandfather, “Flying Wallendas” patriarch Karl Wallenda, fell to his death in 1978 while trying to cross a wire in Puerto Rico. The video is below.

Warning: video is graphic; for mature audiences only.

Beginning at 8 p.m., ABC will air Wallenda-related specials leading up to the tightrope stunt, which is scheduled to take place at approximately 10 p.m.