Neighbors said they heard a loud lightning strike and the flames started to spread quickly.
"I heard the loudest boom of a lightning strike I've ever heard," said neighbor Dave Skebba. "Within a minute, I heard firetrucks come by."
The homeowner, with his dog, was seen being escorted to the scene, where he saw the destruction for the first time.
"They're in shock, understandably, as anybody would be in this situation,” said Carrie Proudfit, with Orange County Fire Rescue. “But they are grateful to first responders here on the scene, and they're grateful that they're not hurt or worse."