One of the strongest hurricanes ever to strike the U.S., Laura barreled across Louisiana on Thursday, shearing off roofs, killing at least six people and maintaining ferocious strength while carving a destructive path hundreds of miles inland.

A full assessment of the damage wrought by the Category 4 system was likely to take days, and the threat of additional damage loomed as new tornado warnings were issued after dark in Arkansas and Mississippi.

But despite a trail of demolished buildings, entire neighborhoods left in ruins and almost 900,000 homes and businesses without power, a sense of relief prevailed that Laura was not the annihilating menace forecasters had feared.

"It is clear that we did not sustain and suffer the absolute, catastrophic damage that we thought was likely," Louisiana Gov. John Bel Edwards said. "But we have sustained a tremendous amount of damage."

He called Laura the most powerful hurricane to strike Louisiana, meaning it surpassed even Katrina, which was a Category 3 storm when it hit in 2005.

The hurricane's top wind speed of 150 mph (241 kph) put it among the strongest systems on record in the U.S. Not until 11 hours after landfall did Laura finally lose hurricane status as it plowed north and thrashed Arkansas, and even by Thursday evening, it remained a tropical storm with winds of 40 mph (65 kph).

The storm came ashore in low-lying Louisiana and clobbered Lake Charles, an industrial and casino city of 80,000 people. On Broad Street, many buildings had partially collapsed, and those that didn't were missing chunks. Windows were blown out, awnings ripped away and trees split in half in eerily misshapen ways. Police spotted a floating casino that came unmoored and hit a bridge. At the local airport, planes were overturned, some on top of each other.

In front of the courthouse was a Confederate statue that local officials had voted to keep in place just days earlier. After Laura, it was toppled.

"It looks like 1,000 tornadoes went through here. It's just destruction everywhere," said Brett Geymann, who rode out the storm with three family members in Moss Bluff, near Lake Charles. He described Laura passing over his house with the roar of a jet engine around 2 a.m.

"There are houses that are totally gone. They were there yesterday, but now gone," he said.

Not long after daybreak gave the first glimpse of the destruction, a massive plume of smoke visible for miles began rising from a chemical plant. Police said the leak was at a facility run by Biolab, which manufactures chemicals used in household cleaners such as Comet bleach scrub and chlorine powder for pools.

Nearby residents were told to close their doors and windows and turn off air conditioners. State and federal aircraft headed into the skies over the coast to look for signs of any other industrial damage.

The fatalities included a 14-year-old girl and a 68-year-old man who died when trees fell on their homes in Louisiana, as well as a 24-year-old man who died of carbon monoxide poisoning from a generator inside his residence. Another man drowned in a boat that sank during the storm, authorities said.

No deaths had been confirmed in Texas, which Republican Gov. Greg Abbott said would amount to "a miracle." Chevellce Dunn considered herself among the fortunate after a night spent huddling on a sofa with her son, daughter and four nieces and nephews as winds rocked their home in Orange, Texas. Left without power in sweltering heat, she didn't know when power might be restored.

"It ain't going to be easy. As long as my kids are fine, I'm fine," Dunn said.

President Donald Trump planned to visit the Gulf Coast this weekend to tour the damage.

More than 580,000 coastal residents evacuated under the shadow of a coronavirus pandemic and calls for masks and social distancing to combat its spread. It was the largest evacuation order since the pandemic began and many people followed it, filling hotels and sleeping in cars. Although not everyone fled from the coast, officials credited those who did leave for minimizing the loss of life.

Forecasters had warned that the storm surge of 15 to 20 feet would be "unsurvivable" and could push 40 miles inland. Edwards said the storm surge wound up being measured in the range of 9 feet to 12 feet — still bad, but far from the worst forecast. He was hopeful that damaged homes could quickly be made habitable.

The priority, Edwards said, was search and rescue, followed by efforts to find hotel or motel rooms for those unable to stay in their homes. Officials in Texas and Louisiana have both sought to avoid traditional mass shelters for evacuees over fears of spreading COVID-19, and Edwards was concerned that the storm would inhibit coronavirus testing as schools and universities are reopening.

Bucky Millet, 78, of Lake Arthur, Louisiana, considered evacuating but decided to ride out the storm with family due to concerns about the coronavirus. He said a small tornado blew the cover off the bed of his pickup and made him think the roof on his house was next.

"You'd hear a crack and a boom and everything shaking," he said.

The force of Laura's winds blew out every window of the living room in the Lake Charles house where Bethany Agosto survived the storm with her sister and two others. They sought safety in a closet when the hurricane was at its worst.

"It was like a jigsaw puzzle in this closet. We were on top of each other, just holding each other and crying," Agosto said.

The storm was so powerful that it could regain strength after turning east and reaching the Atlantic Ocean, potentially threatening the densely populated Northeast.

Laura hit the U.S. after killing nearly two dozen people on the island of Hispaniola, including 20 in Haiti and three in the Dominican Republic, where it knocked out power and caused intense flooding.

It was the seventh named storm to strike the U.S. this year, setting a new record for U.S. landfalls by the end of August. The old record was six in 1886 and 1916, according to Colorado State University hurricane researcher Phil Klotzbach.

Laura was tied with five other storms for fifth most powerful U.S. hurricane, behind the 1935's Labor Day storm, 1969's Camille, 1992's Andrew and 2004's Charley, Klotzbach said.