(Bloomberg) -- Tropical Storm Debby threatens to unleash days of heavy rain and flooding on the US East Coast after slamming into Florida as a hurricane, knocking out power to thousands.
Debby’s top winds dropped to 65 miles per hour, down from 80 mph earlier when it made landfall near Steinhatchee, Florida, the National Hurricane Center said in a 2 p.m. New York time advisory. The storm will continue to weaken but the main danger now is the rain, with as much as 12 inches (30 centimeters) expected to fall across a wide area from northern Florida to North Carolina through Saturday as Debby meanders around the South.
The waters will inundate roads, damage crops and likely drive people from their homes. Some parts of Georgia and the Carolinas may get 30 inches before the storm ends, the hurricane center said.
“This potentially historic rainfall will likely result in areas of catastrophic flooding,” according to the center. “This will likely result in areas of considerable flash and urban flooding, with significant river flooding expected.”
The storm has already cut power to almost 300,000 customers across northern Florida and Georgia, according to PowerOutage.us. It’s also grounded over 1,600 flights around the US, said FlightAware, an airline tracking service.
Governors in Florida, Georgia and South Carolina have all declared emergencies and US 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, Georgia, and Charleston, South Carolina, 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 US 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 lost steam, 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 US this year following Beryl, which struck eastern Texas last month 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 US — 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.
--With assistance from Cedric Sam.
(Updates with top winds in second paragraph, power outages in fifth)
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