And the storm is still expected to bring catastrophic winds, rain, storm surges and flooding, the National Hurricane Center briefing said.
The latest storm surge has some areas under over 8 feet of water.
The utility crews will need to hunker down until the storm passes. "This is a storm that is historic, maybe once in a lifetime".
Maryland's largest natural gas and electric company, BGE, said it was also preparing for the storm.
Meanwhile, those choosing to ride out the storm in evacuation zones are being told first responders will not be available to help them once Florence makes landfall.
"This is not going to be a glancing blow", warned Jeff Byard, an administrator with the Federal Emergency Management Agency.
Florence weakened slightly to a Category 3 storm on a five-step scale but had maximum sustained winds of 125 miles per hour (201 km per hour) as of 2 p.m. EDT (1800 GMT), down from 130 mph earlier in the day.
Forecasters say the storm is likely to remain constant in strength, weakening only after the center of the storm moves inland. Currently, the hurricane-force winds extend outward 80 miles from the center and tropical storm-force winds extend almost 200 miles from the eye.
US President Donald Trump both touted the government's readiness and urged people to get out of the way. The National Weather Service said about 5.25 million people live in areas under hurricane warnings or watches, and 4.9 million in places covered by tropical storm warnings or watches. Florence is now a strong Category 2 storm. The power is going to be off for weeks.
Steering currents - around clear-weather high-pressure systems and stormy low-pressure systems - redirect hurricanes, with the clear-weather systems acting as walls that storms have to go around. This storm is going to be a direct hit.
Many seaports and airports along the southeastern USA coastline have been shut down, more than 1,000 flights have been canceled, and some highways and bridges in low-lying coastal areas could close soon, as Hurricane Florence gets closer to making landfall. According to forecasters, the center of Florence is expected to hit North Carolina's southern coast Friday, then drift southwest before moving inland on Saturday. The storm's size and area affected by hazardous winds have actually expanded, and the threat from storm and rain-induced flooding "have not changed" tweeted Rick Knabb, The Weather Channel's tropical weather expert and former Hurricane Center director.
The last time the USA capital declared a state of emergency was in January 2016 when a winter storm dubbed "Snowzilla" blanketed the capital region in knee-deep snow. "I've never been one to leave for a storm but this one kind of had me spooked". Streets were quiet with schools and many offices and businesses closed.
McMaster warned of possible landslides in the Upstate, portions of which could get drenched with 10 inches of ran over the weekend.
"I said, 'Why get on the road like this?"
Charleston, resident William Belli said he would not be among those joining the exodus.
According to the NHC's forecast discussion at 12 p.m. on September 13: "The subtropical ridge to the northeast and east of Florence is now well-established between Bermuda and the US mid-Atlantic region and extends westward into Virginia and the central Appalachians". "Not anxious in the least".
Up to 1.7 million people have been ordered to evacuate across South Carolina, North Carolina and Virginia.
"This is a life-threatening situation".
"I ask all Georgians to join me in praying for the safety of our people and all those in the path of Hurricane Florence", Deal said. Reacting to the possibility of a more southerly track, Georgia Gov. Nathan Deal declared an emergency but did not immediately order any evacuations.
A smaller hurricane dubbed Isaac is reportedly heading for the Caribbean, while Hurricane Helene - now also in the Atlantic - is forecast to track towards the UK.