With massive Hurricane Irma churning in the Atlantic, any evacuation plans for New Orleans would face at least one unprecedented issue: There would only be one way to go, New Orleans mayor Mitch Landrieu said on Tuesday.

With Texas and southwestern Louisiana still struggling with Hurricane Harvey's aftermath, and Irma likely tearing through Florida, the only way out would be north, Landrieu said in an interview via WWL-TV after a tabletop exercise with other leaders from around the state.

"Everybody in New Orleans and everybody along the Gulf Coast has to be aware that we haven't been in this position before … That can only mean one thing. It can mean that you have to go north," Landrieu said.

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"If you can't go to the left and you can't go the right and you can only go one way, it means you have to leave earlier so as to avoid [that] kind of congestion and traffic. And it means you have to be prepared, which means you have to have fuel. And if something bad happens you need to be able to take care of yourself over time."

Landrieu spoke after a planning exercise on Tuesday to prepare for Irma's potential impact on the United States later this week. The storm strengthened to a Category 5 hurricane on Tuesday and slammed into the Caribbean islands Wednesday with sustained winds up to 185 mph.

Louisiana officials hold hurricane preparation session Louisiana officials walked through how they will respond if the state gets hit by a major hurricane while parts of the Gulf Coast are recoveri…

Landrieu responded to a question regarding the pump systems, saying they're improving every day, but they were never meant to hold up to a high-powered hurricane. Post-Katrina, the plan has always been to evacuate ahead of any storm approximated to be a category 3 or higher.

"Every day we get stronger and soon we'll be back … in a better place than we have been in a very long time. This storm has nothing to do with pumps," Landrieu said. "Once you get to a Category 3, 4 or 5 it doesn't really have anything to do with drainage capacity … it's not what the storm protection system was designed to protect against."

Irma, which was the strongest Atlantic hurricane ever recorded north of the Caribbean and east of the Gulf of Mexico, passed almost directly over the island of Barbuda, according to the U.S. National Hurricane Center in Miami.

The U.S. National Hurricane Center said Irma was "potentially catastrophic" as it bore down on the twin-island nation of Antigua and Barbuda. It was centered about 225 miles east of Antigua in the late morning and moving west at 14 mph.

The island of Anguilla was experiencing "extremely heavy winds and rain," according to the Disaster Management Department and there were reports of flooding, but details were not yet available.

The center of the storm was about 15 miles (25 kilometers) west of St. Martin and Anguilla about 8 a.m. Wednesday, the hurricane center said. It was heading west-northwest at 16 mph (26 km/h).

As the eye of Hurricane Irma passed over Barbuda around 2 a.m., phone lines went down under heavy rain and howling winds that sent debris flying as people huddled in their homes or government shelters.

Irma is the strongest Atlantic hurricane since Rita in 2005, officials said.

A new tropical storm also formed in the Atlantic on Tuesday, to the east of Irma. The hurricane center said Tropical Storm Jose was about 1,505 miles east of the Lesser Antilles with maximum sustained winds of 40 mph. It was moving west-northwest at 13 mph and was expected to become a hurricane by Friday.

The storm is expected to kick north, impacting Florida, but a plan must be in place if that doesn't happen, Landrieu said.

Tropical Storm Katia also formed in the southwestern Gulf on Wednesday, but it is expected to track southwest and make landfall in Mexico.

According to the Hurricane Center, winds will likely fluctuate slightly, but the storm would remain at Category 4 or 5 strength for the next day or two. The most dangerous winds, usually nearest to the eye, were forecast to pass near the northern Virgin Islands and near or just north of Puerto Rico on Wednesday.

President Donald Trump declared emergencies in Florida, Puerto Rico and the U.S. Virgin Islands, and authorities in the Bahamas said they would evacuate six southern islands.

"Whatever is in its way is going to get hurt really, really badly. And that's what the people of New Orleans have to be planning for," Landrieu said. "I want to encourage people to get prepared for whatever might come our way."

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