Hurricane Debby threatens to flood eastern U.S. after hitting Florida

As much as 12 inches of rain is forecast to fall across a wide area from northern Florida to North Carolina this week.

Protective measures are made to a business ahead of Hurricane Debby in Cedar Key, Fla., on Aug. 4. (Photo credit: Bloomberg)

(Bloomberg) — Hurricane Debby threatens to unleash days of heavy rain and flooding along the Eastern Seaboard of the U.S after slamming into Florida near Tallahassee, knocking out power to thousands.

As much as 12 inches of rain is forecast to fall across a wide area from northern Florida to North Carolina this week as Debby meanders around the South, inundating roads, damaging crops and likely driving people from their homes. Some parts of Georgia and the Carolinas may get 30 inches before the storm ends, the U.S. National Hurricane Center said.

“This potentially historic rainfall will likely result in areas of catastrophic flooding,” the hurricane center said in an advisory. “This will likely result in areas of considerable flash and urban flooding, with significant river flooding expected.”

Debby’s top winds dropped to 75 miles (121 kilometers) per hour, just at the threshold for hurricane strength, as it moved northeast about 60 miles from Cedar Key, Fla. The storm has already cut power to more than 250,000 customers across the northern part of the state, according to PowerOutage.us. It’s also grounded over 890 flights around the U.S., said FlightAware, an airline tracking service.

Governors in Florida, Georgia and South Carolina have all declared emergencies, and President Joe Biden has approved federal help. In the immediate path of the storm, residents along the coast were ordered from their homes and shelters have been opened.

If the storm causes widespread flooding across the South, particularly around Savannah, Ga., and Charleston, S.C., it could cause up to $1.5 billion in destruction and losses, said Chuck Watson, a disaster modeler at Enki Research.

In 2018, the southeastern U.S. was devastated by torrential rains from Hurricane Florence that killed more than 50 people and damaged infrastructure and agriculture throughout the region.

Even though Debby will lose steam and its winds will weaken to tropical-storm strength later Monday, the situation across the South will likely get worse because of how slowly the storm will move through the region, said Tyler Roys, a senior meteorologist at commercial forecaster AccuWeather Inc.

“Going forward now, rain is going to be the big factor basically for the rest of Debby’s life,” Roys said. “We’re very worried about this rain.”

Debby is trapped between high-pressure systems to its northwest and northeast and this means there won’t be strong steering currents in the atmosphere to move Debby along, said Phil Klotzbach, a hurricane researcher at Colorado State University.

“There’s certainly going to be catastrophic flooding given how slow-moving Debby is going to be,” he said.

The situation will get worse if Debby re-emerges, as is expected, into the Atlantic Tuesday because it will be pushing water onshore, essentially blocking rivers from draining into the ocean as the downpours continue inland.

Debby is already the second storm to make landfall in the U.S. this year following Beryl, which struck eastern Texas in July and caused a massive power outage. The Atlantic basin typically doesn’t produce its second system with winds of at least 74 mph until August 26.

Western Florida in recent years has been battered by storms including Category 5 Michael in 2018 — which was directly responsible for 16 deaths in the U.S. — and Ian, which struck as a Category 4 storm in 2022, leaving more than 160 dead. A year ago, Hurricane Idalia made landfall in the Big Bend area as a Category 3 hurricane.

In addition to Debby, forecasters are watching an area of unsettled weather in the Atlantic that may push into the western Caribbean later this week. It has a 30% chance of becoming the season’s next storm within seven days.

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