Why North Carolina is vulnerable to hurricanes

More than 1 million people have been issued evacuation orders along the coastal areas of Virginia, North Carolina and SC, as the storm is not expected to weaken until it makes landfall Thursday in the Carolinas.

Florence rapidly intensified over the past 24 hours becoming a Category 4 storm, with maximum sustained winds of up to 140mph.

The National Weather Service calls it a "storm of a lifetime" - and for good reason.

- Where the storm ultimately makes landfall is irrelevant. That forecast could change, however, should the storm's track change.

And the storm surge, which could be as much as 12 feet in some areas, will be on top of sea level rise from climate change.

As of 11 a.m. Tuesday, Hurricane Florence had maximum sustained winds of about 130 miles per hour, a slight weakening from earlier the morning.

The winds will be strong enough to knock down trees, damage structures and cause widespread power outages, the center warned. Multiple states have already declared a state of emergency in preparation for the damaging flooding that Florence is likely to bring.

Forecasters said parts of North Carolina could get 20 inches (50 centimetres) of rain, if not more, with as much as 10 inches (25 centimetres) elsewhere in the state and in Virginia, parts of Maryland and Washington, D.C.

Heavy rainfall - up to 15 inches - for much of northern Virginia and nearly all of the state's eastern half.

As South Carolina braces for Hurricane Florence's potential landfall, Clemson Cooperative Extension agents are offering reminders and resources for maintaining and preparing stormwater ponds in the event that severe weather strikes.

Flooding from a prolonged, heavy rainfall could extend inland over the Carolinas and for hundreds of miles.

Henry McMaster declared a state of emergency September 8, enabling the South Carolina National Guard to activate guard members to get ready to support first responders and counties.

Both counties issued state-of-emergency declarations this morning, joining Currituck County and Chowan County and Edenton, which issued their declarations on Monday, and Elizabeth City, whose declaration took effect this morning.

The two schools had announced earlier in the day that the game wouldn't be played as scheduled Saturday.

On Parris Island, South Carolina, recruits were ordered evacuated from the Marine Corps' biggest training installation on the East Coast.

Even before it officially arrives, Florence will push tall waves far ahead of it. Late Monday afternoon, Maryland's governor declared a state of emergency, joining the governors in both North and SC and Virginia in similar declarations.

"Florence is expected to slow down considerably by late Thursday into Friday", stated the 11 p.m. update from the National Hurricane Center.

But while wind speed offers an easily quantifiable way to rate unsafe storms, forecasters are warning people not to fixate on that, saying that saltwater from the storm surge and freshwater from heavy rains pose a serious threat, no matter what the top winds are when the hurricane makes landfall. "So the call to return the favor to SC now is a very important one for us to answer", Louisiana State Fire Marshal Butch Browning said.

Tuesday afternoon, lanes were reversed on USA 501 and three other SC highways as residents of the coastal area fled from Hurricane Florence, a raging tropical cyclone that is expected to deliver a crippling blow to a large swath of the Mid-Atlantic Coast and inland areas today (Thursday) and tomorrow.