While in Myrtle Beach, South Carolina, many are getting ready for life off the grid, buying up generators, flashlights, water and lots of plywood to cover up windows.
Evacuation shelters will open on Tuesday and be available to individuals based on need, said Kim Stenson, director of the South Carolina Emergency Management Division.
North Carolina Governor Roy Cooper declared a state of emergency as well as mandatory evacuation orders along the eastern coastline. "We are mobilizing the state's resources to make sure we are prepared, and the people of SC must not hesitate to prepare for the possibility of a hurricane impacting our coast".
NOAAAn NOAA map shows the probability of tropical-storm-force winds hitting the US East Coast between Sunday and Friday.
Some 38cm (15in) to 64cm (25in) of rain is forecast in some areas - with up to one metre (40in) at the centre of the storm.
The latest projection for the path of the storm, released Sunday, shows the storm track centered on Wilmington, N.C., with forecasters predicting it will be a "dangerous major hurricane" by the time it reaches the coast later in the week.
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In the Pacific, Hurricane Olivia triggered warnings for multiple Hawaiian islands.
Hurricane-force winds extend outward up to 15 miles from the center and tropical-storm-force winds extend outward up to 115 miles.
As for travelers, airlines serving destinations in Florence's projected path have started waiving change fees and are expecting widespread delays and cancellations.
He warned residents to take precautions "because once this storm is upon us, we're not going to be able to send emergency personnel out to rescue you".
Hugo in 1989 was the last major hurricane to hit the SC coast. President Trump said the hurricane is predicted to be one of the worst storms to hit the East Coast in years as he warned residents to be prepared and to be careful.
A warm ocean is the fuel that powers hurricanes, and Florence will be moving over waters where temperatures are peaking near 30C, hurricane specialist Eric Blake wrote.
The hurricane is expected to dump heavy rain throughout the region and FEMA officials said it's not just a coastal problem.