(CNN) -- An elderly man and his granddaughter died after a bolt of lightning started a fire in a house in Louisville, Kentucky, on Thursday evening, officials said.
The lightning came from powerful storms that struck the area, causing auto accidents, flooding viaducts and stranding cars.
The 911 call from the people inside the house came in around 6:45 p.m., said Vince Luney, communications supervisor for EMA Metrosafe, a public safety agency. Amid a flurry of other emergency calls, firefighters were dispatched to the scene and arrived within minutes.
The elderly man was bedridden and his granddaughter was trying to get him out of the house, said Gregory Frederick, the Louisville fire chief.
It took "about 10 or 15 minutes to actually locate them because of the severity of the fire," he said. "We had to knock some of the fire down to get firefighters in there to effect the rescue. The fire had a pretty good head start on us."
Between them, the 30 firefighters on the scene pulled the two people out of the house.
"Those boys were brave -- the flames were going, they were running straight to it, back up a bit, and run again," Billy Ray Garrett, a resident of the neighborhood told CNN affiliate WAVE. "If anybody died in that house, it ain't because of anything they could do, they were trying, they were fighting."
The elderly man died of his injuries at the scene, according to Frederick, and the woman was declared dead at a Louisville hospital. Several family members were present at the time and were notified, he said.
Firefighters are investigating the blaze and are treating lightning as the preliminary cause.
"Lightning struck an 80-foot-tall tree, hit about 40 feet up, and it entered a phone wire that came in through the rear of the house," Frederick said. Melted wire suggested the phone line had carried the lightning's charge into the basement of the house, he added.
Fire crews reported smoke in the basement upon arrival.
"It was like having a blow torch coming out the side of the house," Garrett said. "It was running all the way up the side of the other house, it was all coming through the bottom window, like a massive torch."
The house is still standing, according to Frederick.
"It's got pretty severe damage to the basement and the first floor," he said. "It's an older, probably 1940s-era house, so the fire traveled (through) sealed spaces and moved into other areas of the house."
Severe thunderstorms that pushed through the area included winds that topped more than 60 mph, according to the National Weather Service. The storms knocked out power in thousands of homes across Kentucky.
The roof of Louisville's Crowne Plaza Hotel was partially torn off, sending debris onto vehicles in the parking lot below, officials said. No injuries were reported to EMA Metrosafe.
"We probably made somewhere in the neighborhood of 300 other runs" to deal with problems caused by the storm, Frederick said. A multitude of those requests came within 20 to 30 minutes, he added.
In nearby Oldham County, a man on a boat on the Ohio River was struck by lightning, said Don Dahl, the North Oldham deputy assistant fire chief.
The young man was in speedboat with about four other people when the storms rolled in from the Indiana side of the river, Dahl said.
The man appeared to have taken a direct hit from lightning and was "hurting pretty bad," according to Dahl.
The emergency services got the man onto land and into a waiting ambulance, which took him to a Louisville hospital, he said.
The man's latest condition was not immediately available. He was taken to the hospital with "unknown injuries," said Jason Smiser, Oldham County dispatcher.