South Carolina's governor ordered the state's entire coastline evacuated starting at noon Tuesday and predicted that 1 million people would flee as highways reverse directions. It is expected to strengthen and possibly become a Category 5 storm Tuesday before closing in on North or SC on Thursday.
A forecast from the hurricane center projected that Florence will pick up speed in the coming days.
"It is an extremely, dangerous, life-threatening, historic hurricane", said North Carolina Gov. Roy Cooper. She grew up on the island chain, and says this will be only the second time she's evacuated.
In addition to flooding the coast with wind-driven storm surges of seawater as high as 12 feet (3.7 m), Florence could drop 20 inches to as much as 30 inches (51-76 cm) of rain in places, posing the risk of deadly flooding miles inland, forecasters said.
The airlines affected by the waivers vary from city to city, but most are now in the path of Florence as meteorologists are tracking the category 4 storm.
It said that this motion is expected to continue for the next few days.
Trump said the hurricane was "one of the worst storms to hit the East Coast in many years".
All inland residents should find out now if you live in a flood prone area.
Sustained winds were 130 miles per hour (215 kph) Tuesday morning, but it remains a Category 4 storm and is expected to intensify to near Category 5 status as it slows over very warm ocean water near North and SC.
Florence grew into a major hurricane on Monday morning and was upgraded again to a Category 4 on the five-step Saffir-Simpson scale of hurricane strength at midday as its top sustained wind speeds reached 130 miles per hour.
"People are getting frantic", assistant manager Nadine Schrock said, adding her shop also sold out of cases of bottled water.
As of Monday evening, Hurricane Florence was moving west-northwest at 13 miles per hour. The latest Category 4 to hit the Carolinas was Hurricane Hazel in 1954.
The hurricane roared from a Category 1 (90 mph) to a Category 4 (130 mph) in just 13 hours, an extremely rapid intensification, Colorado State University meteorologist Phil Klotzbach said.
Isaac is expected to reach landfall in the Caribbean later this week. While the storm is expected to batter spanning the Southeast to the Mid-Atlantic region, it will likely have little to no impact on MA, forecasters say.