South Carolina’s governor has ordered the state’s entire coastline to be evacuated after Hurricane Florence strengthened into a potentially catastrophic category four storm.
The National Hurricane Centre said Florence was expected to be “extremely dangerous” and had maximum sustained wind speeds of 140mph, with further strengthening expected.
It could be close to category five by Tuesday.
It will move over the southwestern Atlantic Ocean between Bermuda and the Bahamas on Tuesday and Wednesday, the centre added, and approach the coast of South Carolina or North Carolina on Thursday.
The first effects are already being seen – rip currents have hit beaches, causing seawater to flow over a state highway.
The storm is expected to linger over the Carolinas once it reaches shore, centre director Ken Graham said.
People well inland are being warned they could lose power and face flooding.
“It’s not just the coast,” Mr Graham said.
“When you stall a system like this and it moves real slow, some of that rainfall can extend well away from the centre.”
Florence’s potential path includes half a dozen nuclear power plants, and pits holding industrial waste.
The governor of Maryland has declared a state of emergency.
Larry Hogan said officials were “preparing for the potential of historic, catastrophic and life-threatening flooding”.
The mayor of Virginia’s capital, Richmond, has also declared a state of emergency.
Levar Stoney has urged residents to gather non-perishable food, water, torches, and batteries.
To the incredible citizens of North Carolina, South Carolina and the entire East Coast – the storm looks very bad! Please take all necessary precautions. We have already began mobilizing our assets to respond accordingly, and we are here for you! pic.twitter.com/g74cyD6b6K
— Donald J. Trump (@realDonaldTrump) September 10, 2018
“The Storms in the Atlantic are very dangerous,” President Donald Trump tweeted.
“We encourage anyone in the path of these storms to prepare themselves and to heed the warnings of State and Local officials.
“The Federal Government is closely monitoring and ready to assist. We are with you!”
Hurricanes are powered by warm oceans, and Florence is moving over waters in areas where temperatures are peaking at about 30C (86F).