Justin Sherman woke up Thursday to an unpleasant surprise: an explosion outside his Echo Lake-area home.

“At about 5 o’clock this morning, it sounded like a stick of dynamite went off, so I went outside and my truck was on fire,” Sherman said.

Sherman called 911 for help and grabbed a garden hose to wet down his house because heat from the blazing 2006 Ford F-350 diesel pickup was beginning to melt siding on the house.

“It was really, really going,” he said. “The fire finally made its way through the cab.”

When that happened, Sherman had to retreat because of a spare fuel tank just behind the cab in the bed of the truck.

“Once that thing went, I had to get away from it,” he said. “It threw up a pretty good mushroom cloud.”

Sherman said the initial explosion rattled the windows of neighbors an eighth of a mile away.

A Bigfork Quick Response Unit was the first to arrive, he said, but eventually there were two fire trucks and a water tender on the scene.

But there wasn’t much left to save because the fire “spread throughout the truck, bumper to bumper, in I would say no less than 15 minutes,” Sherman said. “It was unbelievable.”

The cause of the explosion still is unclear.

“It’s all speculation at this point, but it seems that one of the batteries blew up somehow, some way,” he said. “The fire started under the hood, that’s for sure.”

Sherman had last driven the truck Wednesday. “I drove the truck home last night and everything was fine and dandy,” he said.

Sherman said his insurance company is sending out an investigator to determine the cause.

“I’m still dumbfounded by it. I don’t understand how it happened,” said Sherman, who relied on the truck for his contracting business.

He said the white pickup had been customized just to his liking.

“That’s my luck, though. You get a truck just the way you want it and there it goes,” he said.

Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com