Popping sounds filled the air at Lake Delhi Marina & RV south of Manchester, Iowa, early Wednesday.

Owner Rusty Peck’s two grown sons grabbed their guns and peeked out the window, but there wasn’t any criminal activity brewing outside of the 15,000-square-foot facility.

However, Peck’s sons wandered outside to discover a large fire engulfing their father’s business, leaving mounds of rubble and more than $1 million worth of recreational boats destroyed, according to the Dubuque Telegraph Herald.

Six fire departments responded to the blaze, located in rural Manchester, around 3:30 a.m. 

Crews from Manchester, Delhi, Ryan, Coggon, Delaware and Prairieburg fought the blaze for about four hours, but still encountered additional flare-ups throughout the morning.

No injuries were reported from the fire.

Authorities have not determined the cause of the blaze, but Peck suspects lightning from an early-morning thunderstorm is to blame.

Foul play has been ruled out, said T.J. Carrothers, Ryan Fire Department chief.

The Iowa State Fire Marshal’s Office was called to the scene to investigate the fire, Carrothers said.

Peck, of Delhi, was out of town as the fire erupted at his business. He was startled at the scope of the damage upon arriving at the scene.

“It was much more serious than I thought,” Peck said. “When I got here, there was no roof on the building and flames were coming out of it.”

More than 40 boats were housed in the facility’s showroom, located on its south end, Peck said. The business also carried Four Winds International and KZ RV products.

A warehouse building at the north end of the facility was partially standing after the fire but with its roof caved in.

Firefighters experienced problems initially due to the intensity of the flames, Peck said.

“As soon as they turned around and parked their truck, the roof collapsed and blew all the windows out,” he said. “They had to move their truck because the heat of the fire was so intense.”

With the buildings’ metal interior and exterior, Carrothers said the investigation could become complicated.

“You have to put out the fire by destroying the building, so you don’t know if you are destroying evidence or not,” Carrothers said.

Due to increased demand of the summer season, Peck’s business will remain open.

A temporary operation has been set up at Lake Delhi Marina and RV’s old facility. “We’re up and running. We’re not going to miss a beat. We won’t have any boats for a day or two, but we’ll get some boats in here pretty quick,” Peck said.

Peck contacted his sales representative to convey the urgency of the situation.

“I told them, ‘I need boats, and I need them now,'” Peck said. “I hope they respond quickly.”