Hurricane Florence has hit the US coast, leaving streets inundated with ocean water and tens of thousands of homes without power.

The centre of the hurricane made landfall near Wrightsville, North Carolina, bringing with it life-threatening storm surges and 145km/h winds.

The National Hurricane Centre warned there would be “catastrophic” fresh water flooding over a wide area of the Carolinas.

More than 60 people had to be evacuated from a motel at risk of collapse in Jacksonville. Parts of buildings ripped apart by the storm flew through the air.

Authorities in the North Carolina city of New Bern said there were around 150 people waiting to be rescued from rising flood waters.

A TV station had to evacuate its newsroom in the middle of coverage of the hurricane.

Winds of up to 145km/h have left a trail of destruction in their wake, with 400,000 homes and businesses left without power. Photo: Getty

Staff at New Bern’s WCTI-TV NewsChannel 12 had to abandon their studio after roads around the building began flooding.

The weather service later measured a storm surge 3m deep in the city, which lies on the Neuse River near the Atlantic coast.

In Washington, North Carolina, the wind-swept Pamlico River burst its banks and flooded entire neighbourhoods.

Floodwaters submerged US Highway 264, cutting off a major route to other flood-prone areas along the river.

More than 415,000 homes and businesses were without power on Friday morning, according to poweroutage.us which tracks the nation’s electrical grid.

Screaming winds bent trees and led to near-horizontal rain as Florence’s leading edge whipped the Carolina coast to begin an onslaught that could last for days, leaving a wide area underwater from both heavy downpours and rising seas.

The storm’s intensity diminished as it neared land, with winds dropping to around 145km/h.

Governor Roy Cooper has warned of an impending disaster and requested additional federal disaster assistance.

“The worst of the storm is not yet here but these are early warnings of the days to come,” he said.

Prisoners were affected too. North Carolina corrections officials said more than 3000 people were relocated from adult prisons and juvenile centres in the path of Florence, and more than 300 county prisoners were transferred to state facilities.

Officials said some 1.7 million people in the Carolinas and Virginia were warned to evacuate, but it is unclear how many did.

The homes of about 10 million are under watches or warnings for the hurricane or tropical storm conditions.

Forecasters said conditions will deteriorate as the storm pushes ashore near the North Carolina-South Carolina line and makes its way slowly inland.

Its surge could cover all but a sliver of the Carolina coast under more than 3m of ocean water, and days of downpours could unload more than 90cm of rain, touching off severe flooding.

Although it was once a category 4 hurricane with winds of 225km/h, the hurricane was downgraded to a category 1 on Thursday night.

-AAP