• President Trump declared a state of emergency in Florida, Puerto Rico and the United States Virgin Islands.
Storm damage is reported in Barbuda.
Irma tore the roof off a police station on Barbuda, forcing officers to take shelter in a nearby fire station, The Associated Press reported.
Midcie Francis of the National Office of Disaster Services said that there had been damage to several homes but that the authorities had not yet assessed the extent of the destruction.
Residents and officials were particularly worried about the storm surge. Barbuda is flat, with a maximum elevation of no more than 150 feet, though most of its small population lives in and around the town of Codrington, which is at or close to sea level.
“Unfortunately, in Barbuda there are few buffers if a significant storm surge is experienced,” The Daily Observer newspaper said in an editorial on Monday.
Dario Barthley, a project officer with Cricket West Indies, the sport’s governing body in the region, said in a text message that more than 1,000 residents moved before the storm into the island’s only shelter, leaving hundreds more potentially exposed.
“It’s one of the flattest Caribbean islands, so the devastation will be a lot worse there, sad to say,” Mr. Barthely said.
Residents of Antigua also expressed concern about Barbudans in text messages and on social media. Phone lines to the sister island have been down for hours, leaving most residents there unreachable, Antiguans said.
— KIRK SEMPLE
Hurricane sideswipes Antigua.
Irma produced high gusts of wind across Antigua, in what appeared to be a less-than-eventful hit on the island early Wednesday.
About 4 a.m. local time, the storm was 40 miles north of the island, the National Hurricane Center said.
In the Gambles Terrace neighborhood in St. John’s, the capital city, major structures were still intact and houses showed no significant damage. A few fallen branches littered the streets.
— CARL JOSEPH
Pope’s plane is forced to change route.
The plane flying Pope Francis to Colombia had to change its flight path to avoid Hurricane Irma.
The special Alitalia jetliner, which left Rome on Wednesday morning, was originally scheduled to fly over Puerto Rico and Venezuela before entering Colombian airspace, Reuters reported.
The revised route takes it south of Puerto Rico, flying over the islands of Barbados, Grenada, Tobago and Trinidad.
In Puerto Rico, wary of rising waters.
Irma was expected to pass just north of Puerto Rico, which could help the island avoid major damage, but the authorities still warned residents to watch for rising waters.
“We are letting people know there is an expectation of six to eight inches of rain, with some areas receiving up to 12 inches,” Gov. Ricardo A. Rosselló said at a televised briefing Wednesday morning. “This is a cause of concern for flooding in Puerto Rico. As the history with Harvey states, flooding can become the major cause of death in events of this nature.”
Mr. Rosselló said that about 700 people had sought refuge in shelters across the island, including many in Ponce, on the southern coast. He urged people to leave low-lying areas, and said that the authorities had not yet had to call out the National Guard to get people to leave.
“We are asking citizens to be mindful of the risks,” he said. “Help us help you.”
Puerto Rico was last hit by a Category 5 storm nearly a century ago, said Bryan Norcross, a hurricane specialist at the Weather Channel. That hurricane, known as San Felipe, killed more than 2,700 people in Guadeloupe, Puerto Rico and Florida in September 1928, according to The Associated Press.
Officials in Puerto Rico warned that the island’s fragile electrical grid could be shut down for months in some areas. Mr. Rosselló warned that the powerful winds could thrash the island, its infrastructure, houses and the phone system.
The hurricane could not have come at a worse time for Puerto Rico. The island is the throes of an economic crisis and does not have money for rebuilding.
Stoic residents say major storms are a fact of life.
As the storm bore down late on Tuesday, many residents of the Leeward Islands sounded stoic and battle-tested, saying powerful storms were a fact of life in the region.
“We grew up with this stuff,” Joseph John, a surgeon in Antigua, said by telephone. “We build for it. We have the necessary sustenance for it, like water, generators and so forth, shutters and all that.”
Dr. John, who lives on the coast, was spending the night with a friend who lives inland.
But he and others acknowledged that with the promise of record-high winds, Hurricane Irma could be a new experience for the islands.
“This one is a superstorm, so people are very uptight about this,” he said. “We’re talking 185 right now. I can’t recall any hurricane packing on 185 in my lifetime,” he added, referring to winds of 185 miles per hour.
“There are tons of homes here that aren’t prepared for it obviously,” the surgeon continued, saying that many of the substandard dwellings were in lower-income neighborhoods. “What the heck is going to happen, we don’t know.”
On Wednesday, Elias Hadeed, a retired structural engineer and general contractor in Antigua, said that from his perspective, the storm was “much better than expected.” By 6 a.m., he said, the rains had stopped and there had been “no extensive damage” to his garden and his reinforced concrete home.
He said in a text message, “We are lucky that it shifted a little bit to the north of Antigua, but feel sad for the people in our sister island Barbuda.”
In St. Kitts and Nevis, Commissioner Ian Queeley of the Royal St. Christopher and Nevis Police Force said in a text message on Wednesday that the early reports were encouraging. “Not too bad at this time,” he wrote. “Still plenty rain and strong winds.”
— KIRK SEMPLE
Six islands in the Bahamas are evacuated.
“The price you may pay for not evacuating is your life or serious physical harm,” Prime Minister Hubert Minnis of the Bahamas warned residents.
Evacuees from the southern part of the island chain were being flown to Nassau, the capital, on Wednesday, The A.P. said. Mr. Minnis called the operation the “largest evacuation” in Bahamian history.
Miami area and the Florida Keys are taking no chances.
In Miami-Dade County, Florida’s most populous, the memory of the damage brought in 1992 by Hurricane Andrew, a Category 5 storm, spurred residents to prepare for the arrival of Hurricane Irma earlier than usual.
On Wednesday, Mr. Trump tweeted: “Watching hurricane closely. My team, which has done, and is doing, such a good job in Texas, is already in Florida. No rest for the weary!”
Most projections have Irma slamming into the state by Sunday, although it was unclear where it might make landfall.
Gov. Rick Scott activated the state National Guard and declared a state of emergency.
Evacuation orders for Miami-Dade County were expected Wednesday or early Thursday, Mayor Carlos Gimenez said. Hundreds of thousands of residents are likely to leave their homes as a precaution for what is expected to be unprecedented coastal flooding.
The county expected to open shelters on Wednesday, and ordered schools closed on Thursday.
The Florida Keys, a vulnerable chain of islands, were under a mandatory evacuation order: Wednesday morning for visitors and Wednesday evening for residents. The islands’ three hospitals began evacuating patients on Tuesday.
Hurricane Harvey in Texas was weighing heavily on people’s minds.
“I think because of Texas, people are freaking out,” said Yoseyn Ramos, 24, a Miami resident who said she was worried because she could not find gas anywhere.
Watching Tropical Storm Jose, and Katia.
The National Hurricane Center said that Jose was expected to become a hurricane Wednesday night, and that Tropical Storm Katia had formed in the Gulf of Mexico.