Marines deep in Orange County canyon country hoisted heavy military-grade containers from trucks and pulled out shovels, axes, crowbars — equipment to dig holes for C4-grade explosives.

The mission Tuesday was unusual, if not a first. The plan was to blow up three small dams on Silverado Creek. Boulders would fly, concrete would crumble, rock shrapnel would tear into anything soft.

A U.S. Marines Explosives Ordinance Disposal team prepares to demolish three damns in Silverado Canyon, CA on Tuesday morning, March 21, 2017. (Photo by KEN STEINHARDT,Orange County Register/SCNG)

Just before sunset Tuesday night after a long day of preparation, an explosion demolished the first dam.

“It came apart easier than expected,” said Darrell Vance, district ranger for the National Forest Service.