Hurricane Debby has made landfall at the Big Bend region of Florida's Gulf Coast, with fears of storm surges and catastrophic flooding.

The weather system strengthened into a Category One hurricane late on Sunday and came ashore near Steinhatchee on Monday morning, said the National Hurricane Center (NHC).

It is now forecast to move slowly cross the state, packing 80mph winds and dumping as much as 20 inches (50cm) of rain as it moves north.

The fourth named storm of the season will also hit Georgia and South Carolina hard in the days ahead.

The slow-moving nature of the storm could mean historic amounts of rainfall, said Jamie Rhome, the deputy director of the hurricane center.

"You're talking about catastrophic flooding."

Already the storm's strong winds are impacting Floridians - some 190,000 homes and businesses are without power in the state, according to PowerOutage.com.

Forecasters predicted this hurricane season, which runs from 1 June to 30 November, will be a busy one.

The National Oceanic and Atmospheric Administration (NOAA) issued its most startling warning to date about the current season. Forecasters said there could be up to 25 named storms in 2024.

Between eight and 13 of those storms could develop into hurricanes, the NOAA said.

Hurricane Betty marks the fourth named storm of the year after Tropical Storm Alberto, Hurricane Beryl and Tropical Storm Chris.