SAN JUAN, Puerto Rico (Reuters) – Highly dangerous Category 5 Hurricane Irma rolled toward the Caribbean and southern United States, packing winds of 185 miles per hour (295 km per hour) on Tuesday, even as Texas and Louisiana still reeled from devastating Hurricane Harvey.

Irma’s eye was forecast to cross the northern Leeward Islands, east of Puerto Rico, on Tuesday night or early Wednesday, and hurricane warnings were in place from there to the British and U.S. Virgin Islands and Puerto Rico, the U.S. National Hurricane Center (NHC) said in a statement.

The NHC called Irma a “potentially catastrophic” Category 5 hurricane and tweeted that it was “the strongest hurricane in the Atlantic (Ocean) outside the Caribbean Sea and Gulf of Mexico in NHC records.” Category 5 is the highest NHC designation.

“Preparations should be rushed to completion in the hurricane warning area,” the NHC said.

Irma was about 185 miles (295 km) east-southeast of Barbuda in the eastern Caribbean and moving west at about 14 mph (22 kph), according to the NHC. Maximum sustained winds were 185 mph (295 kph), with hurricane-force winds extending 60 miles (96 km) from the eye.

Puerto Rican Governor Ricardo Rossello urged the 3.4 million residents of the U.S. territory to seek refuge in one of 460 hurricane shelters before the storm is expected to hit as early as Tuesday night.

“This is something without precedent,” Rossello told a news conference. He will ask U.S. President Donald Trump to declare a federal state of emergency even before the storm passes to allow disbursement of U.S. emergency funds.

Florida Governor Rick Scott has declared a state of emergency, and said on Tuesday he also asked Trump to make a “pre-landfall” emergency declaration.

Irma is expected to reach southern Florida on Saturday, and shares in insurance companies with exposure in the state tumbled in Tuesday trading.

“TODAY I‘M NERVOUS”

Gary Randall, head of the Blue Waters Resort on Antigua’s north coast, said the staff had boarded up windows, stripped trees of coconuts and fronds and secured anything that could become a hazard.

“I wasn’t that nervous yesterday, but today I‘m nervous,” Randall said by telephone, adding that he expected the hotel’s beach to be swept away and much of the 108-room property to be flooded.

Hurricane watches were in effect for Guadeloupe, the northern coast of Hispaniola, the Turks and Caicos Islands and the southeastern Bahamas.

Julia Nuñez Rodriguez, a single mother of three who lives north of Santo Domingo, the Dominican capital, was most worried about the potentially high death toll. “I‘m hoping and praying for the best,” she said.

Airlines canceled flights to the region, and American Airlines added three extra flights to Miami from San Juan, St. Kitts and St. Maarten.

Irma could be the second powerful storm to thrash the United States in as many weeks. The Atlantic hurricane season ends on Nov. 30.

Residents of Texas and Louisiana were still reeling from Hurricane Harvey, which struck Texas as a Category 4 hurricane on Aug. 25. It dumped several feet of rain, destroying thousands of homes and businesses, killed an estimated 60 people and displaced more than 1 million others.