East Lyme — Fire officials say a lightning strike is the likely cause of a fire that destroyed a home Wednesday at 40 Cardinal Road in the Flanders section of town.

Fire Marshal Richard Morris said he spoke to several neighbors who reported hearing loud thunder around 6:20 a.m. during the peak of Wednesday's storm.

He said it appeared lightning struck the rear of the home.

"While the fire is still under investigation, it does look like lightning may have caused the fire," said Morris. "We found fresh branches that were broken in the trees."

The National Weather Service issued a severe thunderstorm warning for the region until 7:15 a.m. The storm produced heavy rains, thunder and blustering winds. There were some power outages reported in the area.

Jaimee Szupiany said she and her mother, Suzanne, were house and dog sitting for the family of five who were expected to return Wednesday from a family vacation in Florida.

"My mother heard fire trucks in the neighborhood and she told me to run down the street to find out what was going on," said Szupiany. "My heart sank when I saw it was their house."

Land records show the home is owned by Ernesto and Susan Callegari.

Szupiany said her mother returned the family's beagle, Cammie, around 9 p.m. Tuesday and was going to pick up the dog again Wednesday morning. The family also had two indoor cats. It seems unlikely that any pet could survive the fire, she said.

"I saw the roof collapse when they started to spray it," Szupiany said.

A neighbor at 42 Cardinal Road said around 6:30 a.m. he heard a loud "boom" during the rainstorm. The man, who did not want to be identified, said he lost power, but noticed that another neighbor had not. He said he called the power company.

 "... I went outside to see if everything was OK," he said. "I saw flames coming from the roof and that's when I called 911."

He, too, said the family was out of town.

Neighbor Paul Russell said he heard loud thunder around 6:15 a.m.

"It was so loud it shook the house," he said.

Morris said the fire may have been burning up to 40 minutes before it was reported. Fire crews got to the scene at about 7:16 a.m.

Initially, he said, they fought the blaze from the interior, but the fire was quickly spreading and extending from the basement all the way to the roof, forcing fire crews to battle the blaze from the outside.

He said a state police dog that can detect accelerants was also brought to the scene. He said bringing the state police dog is standard procedure when they investigate a "major fire."

"It was well involved from when we were notified," said Morris.

No injuries were reported, but some firefighters were treated at the scene for heat exhaustion.

The fire took nearly three hours to get under control.

The house was left in ruins. All of the windows on the second story were gone. At one point while firefighters were spraying the roof, it collapsed onto what was left of the second floor.

Morris said an excavator was brought to help fully extinguish the fire since smoldering debris from the collapsed building was trapped in the basement area.

Morris said the family was expected to arrive home from vacation Wednesday evening and planned to stay with neighbors for the time being.

In addition to all of the town's fire departments, fire and emergency crews from Montville, Waterford, the Naval Submarine Base, Old Saybrook and Salem responded to the scene.

A gofundme page has been created for the family at www.gofundme.com/CallegariFamily.

Staff Writer Greg Smith contributed to this report.

i.larraneta@theday.com

Twitter: @larraneta