Hurricane Dorian threatens the US after devastating the Bahamas

The north Bahamas town of Marsh Harbour has been devastated by Dorian, with more than 60% of homes damaged by the storm, the country's Prime Minister Hubert Minnis said at a press conference in the capital Nassau on Tuesday.

Speaking at the National Emergency Management Agency (NEMA) headquarters, Minnis added that "a community outside Treasure Cay, Cooperstown, has been cut off from (the) main population, at least 30 people (are) trapped in the community and were waving yellow flags, sheets, shirts, to bring attention to their survival."

"Our urgent task will be to provide food, water, shelter, safety and security," Minnis said. "Additional food will be delivered by NEMA tomorrow."

The Prime Minister said that Dorian was "the greatest national crisis in our country's history."

The Bahamas have been pummelled by the hurricane, and as officials start to take stock of the damage, other countries are offering support.

Hubert Minnis, the Bahamas prime minister, said on Tuesday that he will speak with Canadian Prime Minister Justin Trudeau on Wednesday morning about Canadian assistance.

Mark Lowcock, the United Nations Under-Secretary-General and Emergency Relief Coordinator, and Barbados Prime Minister Mia Mottley will also visit the Bahamas to provide help.

All operations at Charleston International Airport will cease at 3 p.m. ET on Wednesday, the airport said. 

Depending on the weather conditions, airport operations are expected to resume Friday morning.  

The airport said that it strongly recommends that passengers stay in contact with airlines for up to date information on flight operations and cancellations. 

Passengers can also check the airline's website for updates.

The Hope Town Volunteer Fire & Rescue, a volunteer fire brigade in the Bahamas, gave an overview of the damage across the island chain late Tuesday night.

In Elbow Cay on the Abaco Islands, where Dorian had first made landfall as a Category 5 hurricane on Sunday night, 30% of structures had been demolished and the other 70% were damaged to severely damaged.

Most docks were destroyed and unusable, with 99% of boats sunk, the brigade's Facebook post said.

In Man-O-War Cay, also in the Abacos, "all docks destroyed and every boat sunk," the post said. 90% of structures were damaged to severely damaged, with the remaining 10% destroyed.

In Dickies Cay, all docks were destroyed, with half the structures destroyed and half damaged.

Britain's Queen Elizabeth said she is “shocked and saddened” by the devastation caused by Hurricane Dorian, in a condolence message on Tuesday.

“At this very difficult time, my thoughts and prayers are with those who have seen their homes and property destroyed, and I also send my gratitude to the emergency services and volunteers who are supporting the rescue and recovery effort,” the message also said.

As of 6 a.m. ET on Wednesday, 19,271 customers are without power, according to the Florida Emergency Management site.

The majority of the outages are in Brevard, Flagler, and Volusia counties.

Rescue missions are underway in the Bahamas by civilians who are volunteering to brave treacherous conditions around the island on their own boats and jet skis in an effort to rescue neighbors, friends and strangers.

In Freeport, CNN’s Patrick Oppmann and crew were able to capture these efforts of volunteers, who are working around the clock in harrowing conditions.

The volunteers have been able to save dozens of people who are in “awful shape,” who had been seen swimming in the water, hanging onto roofs, and who had witnessed their relatives carried off by the storm surge.

Intense hurricane conditions are still battering much of the island and several boats and jet skis flipped during the rescue attempts, Oppmann reported.

However, some were hopeful that more rescues would begin Wednesday morning after a coast guard helicopter was seen flying over the island late last night.  

Twenty one counties in Georgia are now under a state of emergency.

Georgia's Governor Brian P. Kemp issued an executive order Wednesday morning, expanding the state of emergency declared last week to now include Appling, Bacon, Bulloch, Clinch, Echols, Evans, Screven, Tattnall, and Ware Counties.

Counties Brantley, Bryan, Camden, Charlton, Chatham, Effingham, Glynn, Liberty, Long, McIntosh, Pierce, and Wayne counties remain under a state of emergency.

Johnny Miller, the mayor of Fernandina Beach, Florida told CNN that the city is prepping for the worst.

"We're starting to feel a little bit of a breeze here now so we expect it to be coming in this afternoon and then going throughout this evening. We've been under mandatory evacuation for days - we look like we're going to take a big hit," Miller told CNN Wednesday.

The city, which is situated between the ocean and a river and is home to more than 12,000 residents, has created large sand barricades across vulnerable swathes of beach in preparation for the storm's arrival.

Miller said that his main concern was over getting people to evacuate before the bridges close.

He added that there's been an "unprecedented response" to the mandatory evacuation.

"We've been through several of these in the past," he added.