A barge loaded with fireworks burst into flames on Whitefish Lake Thursday night just as the grand finale of the annual Fourth of July fireworks show was underway.

Hundreds of spectators lining the lakeshore and dozens of boats filled with onlookers were enjoying the show when a spark from a low-bursting firework started the blaze, Whitefish Fire Chief Tom Kennelly said.

The barge was about 600 feet off City Beach.

The two pyrotechnicians on board dove into the water to safety. No one was injured.

A fire and rescue boat staffed by three Whitefish firefighters was able to extinguish the fire in less than five minutes, Kennelly said. When the city-owned barge was pulled ashore at City Beach, there were still eight unexploded shells onboard.

“This is the first year we’ve had a fire boat on the water,” Kennelly said. “It was purchased a year ago by the Whitefish Rural Fire Service Area and was donated to the city. In past years [such a fire] would have been more difficult to extinguish.”

The deck on the floor of the barge sustained about $1,000 worth of damage, but it wasn’t a total loss.

“It still floats,” Kennelly said.

The barge-fire suppression was part of a long night for Whitefish firefighters, who also responded to two structure fires caused by fireworks.

Early Friday morning, the outer wall of a guest house on Whitefish Lake at 2138 Houston Point Drive caught fire. The call came in at 3:25 a.m., and firefighters had it extinguished by 4:47 a.m. Kennelly estimated the damage at $4,000. No one was injured.

Then firefighters headed to Happy Valley just before 6 a.m., where a storage shed in a backyard on Cougar Trail caught fire from exploding fireworks.

The fire destroyed the shed and its contents and also caused minor damage to a neighbor’s camper, Kennelly said. Damage was estimated at $5,000. No one was injured.

Features editor Lynnette Hintze may be reached at 758-4421 or by email at lhintze@dailyinterlake.com.