An "unsurvivable" monster storm has smashed its way through the southern United States leaving at least one person dead, a trail of destruction and a chemical spill at a major US plant.
Category-4 Hurricane Laura was stronger than 2005's deadly Hurricane Katrina at one point but has since been downgraded to a category one storm as it moves inland, forcing a tidal surge that has been described as a "wall of water".
The hurricane has caused an "extremely dangerous" chemical leak at a plant in Lake Charles, Louisiana, which has breached the city's major highway.
After 10am in Louisiana reports emerged of a fire, reportedly caused by the chemical leak near the city. The leak was flowing over the Interstate 10 highway, according to a report from broadcast meteorologist Brad Sowder. He called it an "extremely dangerous situation".
Officials confirmed on Thursday that a 14-year-old girl was killed when a tree fell on her house during the hurricane.
Meanwhile, first light in the city revealed scenes of heavy destruction including a 22-storey glass building in Lake Charles that had windows smashed out.
Lake Charles Mayor Nic Hunter said the Capital One Tower building "looks like Swiss cheese" in an interview with KPLC. The building is one of the tallest in the city and was also damaged during Hurricane Rita in 2005.
Other images showed flooding across Louisiana and Texas, downed trees, twisted metal poles, a crumpled radio tower and downed power lines throughout the city. Officials haven't been able to assess the full extent of the damage as winds in the area are still too powerful.
'Wall of water' in strongest storm in 165 years
Injuries have been reported as flying glass was ripped from a skyscraper. One person simply said "I am terrified" as they posted footage from inside their unit block of the fierce winds howling outside.
Around 400,000 properties are without power. Hurricane Laura struck the coast of the state of Louisiana as a category-4 storm, tearing through the town of Cameron 210km east of Houston, at about 1.15am local time (4.15pm AEST). Winds of up to 240km/h were measured as Laura pounded into the coast. By comparison, when Katrina hit New Orleans its wind speed was less than Laura at a little over 200km/h.
Hurricane Laura has now been downgraded to a category-1 storm by the National Hurricane Centre (NHC). The storm is expected to remain classified as a hurricane as it moves north through Louisiana to Arkansas.
It is reportedly the strongest storm in 165 years to hit Louisiana, a state that is no stranger to hurricanes. A storm surge warning is in place for an almost 700km stretch of coast from south of Houston to New Orleans – that's not far short of the distance between Melbourne and Adelaide. The NHC warned some of the storm surges might be up to 6m in height and spread as far as 45km/h inland.
"To think that there would be a wall of water over two stories high coming onshore is very difficult for most to conceive, but that is what is going to happen," National Weather Service meteorologist Benjamin Schott told reporters.
"The word 'unsurvivable' is not one that we like to use, and it's one that I've never used before," Schott said of the surge.
The White House released a statement on Thursday morning after the storm made landfall, urging people to "continue to heed the warnings and instructions of your State and local officials as storm hazards will persist long after the storm has passed".
US President Donald Trump is also expected to head to the Federal Emergency Management Agency to be briefed on the hurricane.
Just before the storm hit, the country's National Weather Service was blunt.
"TAKE COVER NOW!" it stated. "Take action now to protect your life!"
Around 150 people are said to have remained in the town of Cameron.
For those people who had remained in their homes, the NHC said the best they could do was "get under a table ... use blankets of pillows to protect your head."
Injuries as skyscrapers 'shredded'
CNN Meteorologist Tom Sater said Cameron, which is only 1.5 metres above sea level, "was mostly completely underwater. There will not be a chance to get to that area until late in the morning."
The storm then passed over Lake Charles and weakened to a category-2 storm. But had still been packing wind of almost 180km/h.
In Lake Charles, close to the coast, injuries have also been reported. On Twitter, storm chaser Jeff Piotrowski said flying glass from skyscrapers had fallen on people below. Other footage showed the roof being ripped off a hotel in the city with people apparently in rooms below and glass shorn off office buildings.
CNN has reported that people who have not evacuated are being told to do a grim task by writing down their name and placing it in their pocket inside a plastic bag. Louisiana officials have said rescue efforts will not start until the storm surge has gone.
"Those choosing to stay and face this very dangerous storm must understand that rescue efforts cannot and will not begin until after storm and surge has passed and it is safe to do so," the Vermilion Parish Sheriff's Office said in a statement on Thursday.
"Please evacuate, and if you choose to stay and we can't get to you, write your name, address, social security number and next of kin and put it a Ziploc bag in your pocket. Praying that it does not come to this."
Forecasters have said the storm is so strong it could remain a category-1 hurricane by the time it reaches Little Rock, Arkansas, some 400km inland.
Earlier, Texas Governor Greg Abbott said people had to take Laura seriously.
"The power of Hurricane Laura is unprecedented, and Texans must take action now to get out of harm's way and protect themselves," he said.
"The conditions of this storm are unsurvivable, and I urge southeast Texans to take advantage of these final few hours to evacuate.
"Your property can be replaced," Abbott said. "Your life cannot be replaced."
President Trump told residents in the path of the storm to "listen to local officials".
"Hurricane Laura is a very dangerous and rapidly intensifying hurricane," Trump tweeted. "My administration remains fully engaged with state and local emergency managers."
New Orleans emptied of people
Jimmy Ray was among those heeding evacuation orders in Lake Charles, Louisiana.
"We were going to try to ride it out at the house, but we found out that it was going to be too bad," Ray told AFP outside an evacuation facility.
Another evacuee in Lake Charles, Patricia Como, said her sister, her brother, cousins and other family members had stayed behind but she was "not going to take a chance".
"I'm not going to play with the good lord," Como said.
In New Orleans, devastated by Hurricane Katrina in 2005, the historic French Quarter was empty of tourists, while sandbags were piled up in front of the doorways of colonial-style buildings and windows were boarded up with plywood.
The city remains traumatised from Katrina, which made landfall as a category-3 storm, flooding 80 per cent of the city and killing more than 1800 people.
Laura earlier caused flooding in Haiti and the Dominican Republic, killing at least 25 people.
In Cuba, it caused material damage but no deaths.
The Atlantic storm season, which runs through to November, could be one of the busiest ever this year, with the NHC predicting as many as 25 named storms. Laura is the 12th so far.