Parts of the state of North Carolina are being evacuated as Hurricane Florence strengthened into a major Category 4 hurricane, packing winds of up to 195 kilometers an hour in the North Atlantic Ocean. "With Florence strengthening into a hurricane this morning and continuing to move west, Florida families need to remain alert and remember that storms like this can change course and strengthen at any moment", said Gov. Rick Scott.
North Carolina Gov. Roy Cooper said his state is "in the bullseye" and urged people to "get ready now".
According to USA Today, the National Hurricane Centre has said Florence is set to hit the US East Coast later this week, possibly as early as Wednesday. Once the storm makes landfall, McMaster said, it's expected to move slowly, dumping extreme amounts of rain likely to cause flooding.
He also tweeted that this was "one of the worst storms to hit the East Coast in many years".
About 1 million people have been ordered to flee the entire SC coast beginning at noon Tuesday. Virginia's governor ordered a mandatory evacuation for some residents of low-lying coastal areas, while some coastal counties in North Carolina have done the same.
National Hurricane Center Director Ken Graham also warned that Florence is expected to linger once onshore, downing trees, knocking out electricity and causing widespread flooding. The Department of Homeland Security and the Federal Emergency Management Agency (FEMA) will coordinate response efforts, according to Trump's order.
Travel dates covered also vary, but most are focusing on the dates between Thursday, Sept. 13 and Sunday, Sept. 16. Tropical storm force winds extend 150 miles from the center.
US President Donald Trump has cancelled a political rally planned for Friday in Jackson, Mississippi, over safety concerns related to Florence, his campaign said.
The US Navy said it was preparing to send about 30 ships stationed in Virginia out to sea.
The threat for life-threatening conditions from Hurricane Florence in North Carolina is increasing.
Last week, Florence became the first major hurricane of the 2018 Atlantic season.
Cape Hatteras in North Carolina recorded 68cm or 27in of rain (around 170% of the average) again making it the wettest summer in 62 years of records.