A drone view shows houses and streets flooded as Hurricane Debby affects the gulf coast in Suwannee, Florida, U.S., August 5, 2024. / Reuters/Ricardo Arduengo

STEINHATCHEE, Florida (Reuters) -Tropical Storm Debby drenched northern Florida on Aug.5 and killed several people as the downgraded hurricane churned toward Georgia and the Carolinas, threatening a week of torrential downpours and flooding across the region.

The slow-moving storm plowed into Florida's Gulf Coast around 7 a.m. (1100 GMT) on Aug.5 morning as a Category 1 hurricane, making landfall near Steinhatchee about 70 miles (115 km) southeast of Tallahassee, the National Hurricane Center said.

The storm carried hurricane-force winds of up to 80 mph (130 kph) when it struck in the Big Bend region - where the state's Panhandle meets its main north-south Peninsula - but speeds ebbed as Debby pushed over land.

Trees felled in the storm killed a 12-year-old girl and a 13-year-old boy in Levy County, officials and law enforcement said. A 19-year-old man was killed near Valdosta, Georgia, when a tree fell onto a porch, police said.

Others killed in the storm included a truck driver who lost control of an 18-wheeler on Interstate 75 and went into the Tampa Bypass Canal, and a 38-year-old woman and her 12-year-old son whose SUV crashed in Dixie County north of Tampa in stormy weather, according to law enforcement.

Roughly 150,000 customers were without power on Aug.5 night in Florida, down from a peak of 350,000, according to Poweroutage.us, and flight trackers showed hundreds of flights originating from and heading to Florida airports were canceled on Aug.5.

Vice President Kamala Harris postponed a campaign stop scheduled this week in Savannah, Georgia, the Savannah Morning News reported.

More than 500 people were rescued from flood waters from homes and vehicles in Sarasota, Florida, on Aug.5, police said, and about 180 people were rescued in Manatee County, officials said.

The hurricane center said Debby would cross Georgia and move offshore into the Atlantic Ocean by Tuesday night, then re-strengthen and make a second landfall, probably in South Carolina near Charleston.

The storm was near the Florida-Georgia border late on Monday, about 35 miles (60 km) west of Brunswick, Georgia, and crawling at 7 mph (11 kph) northeast with sustained winds of 45 mph (75 kph) and higher gusts, the hurricane center said.

The center forecast "catastrophic flooding," with some areas along the Atlantic coast receiving 20 to 30 inches (76 cm) of rain by Friday morning. The governors of Georgia, South Carolina and North Carolina declared states of emergency in anticipation of Debby's damage.

By late afternoon on Aug.5, Debby had already dumped eight to 16 inches of rain in some parts of central Florida, according to local weather reports.

"This is going to be an event that is going to be probably here for the next five to seven days, maybe as long as 10 days, depending on how much rainfall we get," said Kevin Guthrie, executive director of the Florida Division of Emergency Management.

Officials in Georgia and South Carolina braced for flooding.

"It may be the most water we've seen in a long while," South Carolina Governor Henry McMaster said at a briefing. "There may be flooding in areas that never flooded in the past."

Savannah Mayor Van Johnson said the city could expect a "once in a thousand year" rain event.

"This will literally create islands in the city," Johnson said.

SLOW DRENCHING

A slow-moving tropical storm as it passed over Cuba, Debby gained strength from exceptionally warm Gulf waters as it paralleled Florida's Gulf Coast on Aug.4.

Debby bears some of the hallmarks of Hurricane Harvey, which hit Corpus Christi, Texas, in August 2017. Downgraded to a tropical storm as it moved inland, Harvey lingered over Texas, dumping about 50 inches of rain on Houston and causing $125 billion in damage.

Climate scientists believe man-made global warming from burning fossil fuels has raised the temperature of the oceans, making storms bigger and more devastating.

The last hurricane to make a direct hit on the Big Bend region was Hurricane Idalia, which briefly gained Category 4 strength before making landfall as a Category 3 in August 2023, with winds of more than 125 mph. The National Centers for Environmental Information estimated $3.5 billion in damages. Florida Gov. Ron DeSantis described the initial effects of Debby as "modest" compared with Idalia.

Forecasters expect numerous Atlantic hurricanes in the 2024 season, which began on June.1, including four to seven major ones. That would exceed the record-breaking 2005 season that spawned the devastating Katrina and Rita hurricanes.

Only one other hurricane, Beryl, has formed in the Atlantic this year. The earliest Category 5 storm on record, it struck the Caribbean and Mexico's Yucatan peninsula before rolling up the Gulf Coast of Texas as a Category 1 storm, with sustained winds up to 95 mph.