As Hurricane Laura raced toward the Gulf Coast, the storm was expected to intensify to Category 4 strength, the National Hurricane Center said.
Gov. John Bel Edwards of Louisiana warned residents that the window to safely flee would soon be closing.
The storm is expected to make landfall early on Thursday morning, but meteorologists said powerful gusts of wind and heavy rains would arrive much sooner, as early as Wednesday afternoon.
“This is a major hurricane,” Mr. Edwards, a Democrat, said during a briefing on Tuesday evening, beseeching residents again to quickly decide if they were going to evacuate and then start moving. “It’s going to be a large, powerful storm.”
The center of the storm is bound for the Texas-Louisiana border. But a vast and heavily populated stretch of the Gulf Coast is bracing for the possibility of hurricane-level conditions, reaching from west of Galveston Island in Texas to Morgan City, La.
Hurricane-strength winds were expected in that region starting on Wednesday night, the National Hurricane Center said. It warned that as the storm moved north, Laura was likely to produce a “life-threatening storm surge, extreme winds and flash flooding” over eastern Texas and Louisiana.The surge could reach as far as 30 miles inland from Louisiana’s southwestern coast, and produce “potentially catastrophic flooding” from San Luis Pass, Texas, to the mouth of the Mississippi River, the center said.
Officials warned of storm surges across the coastline, reaching in some places as high as 13 feet, as well as powerful winds. There is also the threat of flash floods and tornadoes further inland, with the potential for the storm to maintain hurricane strength as it pushes north toward Shreveport, La.
“We’re going to have significant flooding in places that we don’t ordinarily see it,” Mr. Edwards said.
City and county officials in Texas and Louisiana have issued evacuation orders affecting about 500,000 residents, particularly those living in low-lying areas. In Texas, thousands of emergency workers, including the National Guard, were poised to spring into action with boats, aircraft and other equipment when the storm hits.
“There will be a lot of devastation wrecked upon Texas as the storm sweeps through,” Gov. Greg Abbott of Texas said during a briefing on Tuesday.
Laura has drawn comparisons to Hurricane Rita, which smashed the region in 2005.
Laura was approaching the United States on the anniversary of another major Houston-area storm, Hurricane Harvey, which made landfall in Texas on Aug. 25, 2017, lashing the Gulf Coast with extensive flooding and causing nearly $125 billion in damage.
But Mr. Edwards drew a comparison to another storm, one of the most devastating to hit the region: Hurricane Rita, in 2005, which caused an estimated $25.2 billion in damage. He said the storms resembled each other in their paths and intensity.
Memories of Rita, which left a deep physical and emotional toll on the region, remain vivid for many, even 15 years later.
“That point of reference sometimes helps people understand the seriousness of the situation,” Mr. Edwards said.
This week also marks 15 years since Hurricane Katrina slammed into the Gulf Coast, overwhelming a poorly designed levee and drainage system and swamping much of New Orleans. The commemorations will mostly be understated because of the coronavirus pandemic.
The coronavirus is complicating evacuation and potential rescue efforts.
As Hurricane Laura approaches, officials are urging residents not to drop their guard against the coronavirus.
“Remember, just because a hurricane is coming to Texas, does not mean that Covid-19 either has or is going to leave Texas,” Gov. Greg Abbott said at a briefing on Tuesday, reminding residents to keep maintaining social distance and wearing face masks.
Although large shelters are being set up throughout the hurricane zone, the governor encouraged evacuees to consider booking rooms in hotels and motels instead of using shelters, as a safer way to isolate themselves from others who might be infected.
Mr. Abbott and Chief Nim Kidd of the Texas Division of Emergency Management said buses used for evacuations would carry fewer people than in the past, to let riders stay a safe distance from one another. Planners are bringing in more buses than in previous disasters, to make up for having fewer people on each bus.
Traditional shelters like gymnasiums and convention centers that have hosted hundreds of evacuees in past disasters will be set up to provide “layers of separation” between the occupants, Mr. Abbott said. The shelters and buses will be supplied with hand sanitizer and personal protective equipment like face masks, and state officials plan to dispatch testing teams to the larger shelters.
“The state and local governments are fully aware that they are dealing with a pandemic while they are responding to Hurricane Laura,” the governor said.
Reporting was contributed by Giulia McDonnell Nieto del Rio, David Montgomery, Campbell Robertson and Rick Rojas.