Updated 9:20 p.m. ET

"Dirty water everywhere."

That's how Jacqueline Charles of the Miami Herald described the situation in Port-au-Prince, Haiti, in an interview with NPR Wednesday morning. "A lot of rain and a lot of wind," she said. "Before [Hurricane] Matthew, the ground was already saturated, so the idea that you could have 25 inches of rain is a very scary thought."

Charles says state and local governments are so cash-strapped, they do not have the capacity to move people, even after voluntary evacuation orders were issued as the storm lashed the island Tuesday.

Haitian authorities say at least 11 people in Haiti died in the storm, according to The Associated Press, and the hardest-hit parts of the country are inaccessible. The bridge leading south out of the capital has collapsed, Charles says.

The United Nations disaster risk agency says the scale of the destruction in the most remote parts of Haiti's southwestern peninsula is still unknown. Roads have been washed out, communication to much of the region is cut off and aid organizations say they are deeply concerned about a spike in cholera cases.

Roads around the largest hospital in southern Haiti, St. Boniface, are washed out, according to Louise Ivers, who leads cholera treatment and prevention for the medical aid group Partners in Health, which supports the hospital.

"We were already in a cholera crisis in Haiti before the Hurricane," she said, explaining that there had been 26,000 cases of the potentially deadly waterborne disease so far this year. "St. Boniface has a cholera treatment center, but it's going to be very difficult to get supplies out there."

Ivers says she expects it will be at least another day before the scale of the destruction in southern Haiti starts to become clear.

The U.S. Marines say they have deployed 300 people on the USS Mesa Verde ship in anticipation of a disaster relief mission.

As the storm continues to move north, the Bahamas and southeastern U.S. states are preparing for the worst. As of Wednesday morning, Hurricane Matthew was a Category 3 storm, according to the National Hurricane Center.

"Everybody here is very alert, they're very active, they're very concerned," Keith Cooper, who runs an ecotour company on Grand Bahama island and coordinates the Bahamas air sea rescue association, told NPR's newscast unit.

"Lumber's a big thing... for boarding up your homes and stuff," he said. "[Tuesday] it was two tractor trailers of plywood that came in. That went in a matter of minutes."

On Wednesday, President Obama was briefed by Federal Emergency Management Agency. "I want to emphasize to the public — this is a serious storm," Obama said, according to Reuters. "It has been building strength on its way to Florida."

Florida Gov. Rick Scott declared a state of emergency for every county in the state to "ensure we have resources for evacuations, sheltering and other logistical needs." On Tuesday, he announced he is activating hundreds of members of the Florida National Guard to help communities prepare.

Mandatory evacuations go into effect for the barrier islands of Florida's Brevard county as of 3 p.m. ET Wednesday. In St. Lucie, Flagler and Duval counties voluntary evacuations have begun, according to a statement from Scott's office.

Some schools in the southern part of the state are closing early, ahead of the storm, the governor's office said.

The National Hurricane Center predicts the storm will be "very near the east coast of Florida by Thursday evening."

Georgia Gov. Nathan Deal also declared a state of emergency for 30 counties.

In South Carolina, Gov. Nikki Haley said at a press conference she had declared a state of emergency and would close 31 coastal schools and evacuate about a million people from the coast beginning Wednesday afternoon. "Fill your car up with fuel," she told residents.

In a statement Wednesday morning, Haley announced the coastal counties of Charleston and Beaufort should begin evacuating "no later than 3 p.m." and that the state would begin closing eastbound lanes of I-26 and I-77 heading toward Charleston to make room for westbound traffic.

North Carolina Gov. Pat McCrory declared a state of emergency for portions of his state as well. In coastal Hyde County, visitors to Okracoke Island are under mandatory evacuation as of Wednesday morning, and ferries are running on a special schedule to move people to the mainland.

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