A half marathon went on despite flash flooding in New Jersey — with a shirtless former “Bachelorette” star among those filming themselves being forced to wade through waist-high water.

Wild video shows runners clinging to railings as they fight to avoid getting swept away during Sunday’s Racefaster Half Marathon in Paramus, Bergen County.

“Bro, this is nuts!” former “The Bachelorette” contestant Zac Clark said in cell phone footage, as he pans the camera to show himself and other runners up to their knees on an underpass on the trail

Many runners questioned why the race had still gone ahead, despite local flash flood warnings. Organizers instead postponed it by two hours, starting at 10 a.m. instead of the planned 8 a.m.

“I started getting all these national flood warnings for the area saying, ‘Flash flood warning, watch out,’” Garrett Nathan told NBC New York.

“I keep checking my email from the race directors and get no notifications about them canceling, so I’m like, ‘OK,’” he said of his decision to run despite his hesitation.

Paramus got between four and five inches of rain on Sunday, pooling in several spots along the course, especially around the Saddle River.

Despite the treacherous conditions, around 250 runners still completed the race.

Organizers of the Race Faster Half Marathon didn’t respond immediately to requests for comment.