The storm made landfall near the Texas-Louisiana border early Thursday as a Category 4 major hurricane with a maximum sustained wind speed of 150 mph.
Parts of eastern Texas and western Louisiana are forecast to see "catastrophic wind damage," especially in places where the storm's eyewall came ashore, the National Hurricane Center said. Residents in affected areas were urged to evacuate and brace for damaging winds and flooding rainfall that will spread well inland across parts of those areas.
Here's how the news is developing today. All times Eastern. Please refresh this page for updates.
4:13 p.m.: 840,003 without power in Louisiana and Texas
840,003 are currently without power in Louisiana and Texas, according to poweroutage.us.
The breakdown: There are 599,537 without power in Louisiana and 240,466 in Texas.
Not included in the total amount are 43,087 experiencing power outages in Arkansas and 12,633 in Mississippi.
2:10 p.m.: Cameron Parish begins assessing damage left behind
Emergency officials in Cameron Parish, Louisiana, have begun assessing damage caused by strong winds and reported tornadoes in the area. Officials said they had a lot of structural damages, but feel they were very lucky because they don't have as much water damage as feared. They said they hadn't reached out to all the residents who stayed behind, but there had been no real rescue calls reported, just welfare checks.
Officials will conduct a flyover examination with the governor this afternoon to further assess.
1:50 p.m.: Some 731,436 left without power
At least 731,436 customers in Louisiana and Texas were left without power as of Thursday afternoon, up from 671,307 earlier, as officials worked to recover in the wake of coastal storm surges and destructive flash flooding.
Louisiana saw the bulk of the outages with 596,976, while Texas reported about 134,460, down from about 137,376 earlier.
1: 20 p.m.: Authorities battle chemical leak in storm's wake
Louisiana Gov. John Bel Edwards urged residents to stay inside, close their doors and turn off air conditioning units as authorities battled a reported chemical fire just west of Lake Charles.
The fire at the BioLab chemical manufacturing facility in Westlake, Louisiana, was reported early Thursday as emergency officials battled the effects of Hurricane Laura. Louisiana State Police Emergency Services Unit described the fire as a "a hazardous material incident involving a chlorine leak" in the wake of the storm.
Residents in the area were advised to shelter in place and avoid unnecessary travel until further notice.
1 p.m.: Laura weakens further to tropical storm
Laura weakened to a tropical storm early Thursday afternoon with sustained winds of 70 mph. It was last moving north at about 15 mph. The storm's center is roughly 50 miles east southeast of Shreveport, Louisiana. The storm blanketed southern Arkansas with heavy rain and strong gusty winds as it moved northward, bringing the threat of flash flooding. Flash flood warnings remain in effect across northwestern Louisiana, where the heavy rain just moved through over the past few hours.
12:50 p.m.: President Trump approves Arkansas emergency declaration
President Donald Trump approved Arkansas' request for federal emergency assistance as Hurricane Laura makes its way toward the state.
The order authorizes the Department of Homeland Security and Federal Emergency Management Agency to coordinate all disaster relief efforts "which have the purpose of alleviating the hardship and suffering caused by the emergency on the local population," FEMA said in a statement.
Specifically, FEMA is authorized to identify, mobilize and provide at its discretion, equipment and resources necessary to alleviate the impacts of the emergency, FEMA said.
12:10 p.m.: More than 671,000 left without power in Laura's wake
At least 671,307 residents in Louisiana and Texas were left without power as of Thursday afternoon as officials worked to recover in the wake of coastal storm surges and destructive flash flooding.
Louisiana saw the bulk of the outages with 553,931, while Texas reported about 137,376.
11:20 a.m.: Laura continues to weaken, damaging winds and flooding spreads inland
As of late Thursday morning, Hurricane Laura had weakened to a Category 1 with winds of about 75 mph, bringing it closer to tropical storm territory. Flooding is still a major concern as high water levels were still being reported along portions of the Gulf Coast.
It's forecast to weaken to a tropical storm within the next few hours and track northeast toward Arkansas before moving southwest toward Missouri overnight. Forecasters said it will likely be downgraded to a tropical depression by early Friday morning.
11:00 a.m.: President Trump 'commitment' to aiding affected communities
President Donald Trump has been receiving "regular updates" on Hurricane Laura amid ongoing preparations for a major White House celebration Thursday night to close out the RNC, according to the White House.
"As we begin to assess the damage, please continue to heed the warnings and instructions of your State and local officials as storm hazards will persist long after the storm has passed," White House Press Secretary Kayleigh McEnany said in a statement. "Hurricane Laura remains a deadly hurricane with devastating coastal storm surges, destructive winds, and flash flooding." "President Trump is committed to deploying the full resources of the Federal Government to rescue those in distress, support those in the region affected, and restore disruptions to our communities and infrastructure," she added.
The president is scheduled to meet with FEMA officials Thursday afternoon.
10:37 a.m.: 634,021 customers without power in Louisiana and Texas
The number of people without power in Louisiana and Texas continued to climb Thursday morning as Hurricane Laura churned further inland.
By 10:33 a.m. Eastern Time, there were 507,262 customers without power in Louisiana and 126,759 customers without power in Texas, according to PowerOutage.US.
Images from the affected areas show dozens of downed power lines, debris strewn in the streets and damaged buildings with blown-out windows.
10:24 a.m.: Hurricane Laura weakens to a Category 1 with a 'life-threatening storm surge'
Hurricane Laura is now a Category 1 storm, with maximum sustained winds of 85 mph, according to the National Hurricane Center.
However, damaging winds and flooding rainfall are still spreading inland over western and central Louisiana, while a "life-threatening storm surge continues along much of the Louisiana coastline," the weather service warned in its forecast at 9 a.m. Central Time.
9:41 a.m.: Louisiana governor reports 1st known storm-related death
A 14-year-old girl in Louisiana is the first known fatality from Hurricane Laura, according to Louisiana Gov. John Bel Edwards.
Edwards confirmed the death during an interview Thursday morning with MSNBC, saying that the girl died when a tree fell on her home in the Leesville area.
"I suspect that won't be the last, though I pray we don't have any more," Edwards told MSNBC. "But we know we have at least one fatality now in Louisiana."
The governor's communications director, Mike Steel, later confirmed the death to ABC News.
9:25 a.m.: 508,109 customers without power in Louisiana and Texas
Power outages across Louisiana and Texas climbed to more than half a million customers on Thursday morning, as Hurricane Laura battered the coastline.
By 8:15 a.m. Eastern Time, there were 403,921 customers without power in Louisiana and 104,188 customers without power in Texas, according to PowerOutage.US.
8:30 a.m.: 'Those evacuations did save lives,' Texas governor says
Texas Gov. Greg Abbott said no deaths have been reported in the state so far, which he noted was "really premature" as Hurricane Laura "continues to sweep through Texas in an unprecedented fashion."
"Because it's not just where the surge came in, but going up north and Jasper and Center Texas, all the way up to Marshall, Texas," Abbott told "Good Morning America." "So in northeast Texas, a hurricane is going through there for as far as I know the first time ever, so this is truly unprecedented."
As many as 10,000 people have evacuated their homes in Texas, particularly in the southeastern area of the state along the coast and near the border with Louisiana, according to Abbott.
"It could have been a lifesaver," he said. "That may be one reason why we don't have any reports of loss of life yet. We still don't know how many people may be injured. We will be learning that here shortly as the sun rises, and we have search and rescue teams in place to make sure that everybody is going to be safe."
Abbott emphasized the importance of early evacuations ahead of a powerful hurricane like Laura.
"Those evacuations did save lives," he said.
7:56 a.m.: Dozens of families didn't evacuate, Louisiana lieutenant governor says
Louisiana Lt. Gov. Billy Nungesser said he's heard of dozens of families who didn't heed evacuation orders and decided to stay behind.
"Some people just don't want to leave their belongings," Nungesser told ABC News in an interview Thursday on "Good Morning America." "It's hard to get them to leave sometimes."
Nungesser recalled his own decision to ride out Hurricane Katrina back in 2005, as the large Category 5 storm battered New Orleans.
"I know what I went through," he said. "Not a good decision."
Emergency crews will be dispatched to check on residents and survey the damage "as soon as it's safe" to do so, according to the lieutenant governor.
"We're hopeful that we don't find people that didn't make it," he added.
7:18 a.m.: Woman describes moment storm rips roof off home as family hides under kitchen table
Ashley Thompson and her family decided to ride out the hurricane at their home in Louisiana, where many residents were ordered to evacuate.
"We thought we were safe. We had generators, we had windows boarded up," Thompson said in telephone interview Thursday on "Good Morning America."
But the storm ended up being "much worse" than they thought, she said. The winds picked up in the early morning hours around 2 a.m. local time, as Hurricane Laura approached Louisiana's shores.
"We got our family in our home under the kitchen table," she said. "After being under the kitchen table for about five minutes, we lost our roof."
Thompson and her family ran from their home and broke into a nearby house that was empty and under construction. They took cover there with other families in the neighborhood who were also riding out the storm.
Thompson said there are felled trees and power lines in their neighborhood and they hope first responders will come as soon as weather conditions improve.
"We are safe and everyone is unhurt," she said. "But when they become available and people start moving, we will need help."
6:22 a.m.: Laura weakens to Category 2 hurricane, hundreds of thousands without power in Texas, Louisiana
Laura weakened further Thursday morning and is now a Category 2 hurricane with winds up to 110 mph. Hurricane conditions are spreading farther inland across southwestern Louisiana.
Hurricane Laura is now about 45 miles north, northwest of Lake Charles, Louisiana, and is still moving north at 15 mph.
Alexandria, Louisiana, is seeing wind gusts up to 85 mph while winds at Beauregard Regional Airport are gusting up to 82 mph.
There is still a tornado watch in effect for much of Louisiana, eastern Texas, and southwest Mississippi. This tornado watch is in effect until 8 a.m.
Flash flood warnings in the Lake Charles area have been extended until 8:15 a.m. Between 5 and 6 inches of rain has fallen and flash flooding is "ongoing or expected to begin shortly," according to the National Weather Service.
As the storm barreled through the Gulf Coast, more than 382,000 customers are without power in Texas (75,571) and Louisiana (306,499).
Much of Louisiana is now under Flash Flood Warnings, with as much as 4-5 inches of rain.
5:05 a.m.: Laura now a Category 3 hurricane, with winds of 120 mph
Hurricane Laura is now a Category 3 storm with winds up to 120 mph.
It is moving northward through Louisiana as catastrophic storm surge, extreme winds and flash flooding continue.
Despite the storm being a Category 3 now, the National Hurricane Center said Laura can still cause an "unsurvivable storm surge with large and destructive waves." The damage will cause "catastrophic damage" and floodwaters are not expected to recede for several days, according to the weather service.
Hurricane-force winds are expected to continue Thursday morning with catastrophic wind damage expected nears Laura's eyewall, according to the National Hurricane Center.
"Hurricane-force winds and widespread damaging wind gusts will continue to spread well inland into portions of extreme eastern Texas and western Louisiana through the day," the weather service said in its 5 a.m. advisory
The storm is about 30 miles north, northwest of Lake Charles, Louisiana. Laura is still moving north at 15 mph and the hurricane-force winds extend 60 miles from its center.
4:15 a.m.: First damage reports come in, more than 290,000 without power
Hurricane Laura may be slightly weakening as it moves north over land, but it's still churning with winds up to 130 mph. Now more than 290,000 customers are without power in Louisiana (231,944) and Texas (61,153).
On live radar, you can see the eye moving north of Lake Charles, Louisiana. Hurricane winds likely extending well into Louisiana now. An extreme wind warning has been extended until 5 a.m.
The storm is about 15 miles west, northwest of Lake Charles and is moving north at 15 mph.
A tornado watch for the region, which includes New Orleans, remains in effect until 9 a.m. Other tornado warnings are well removed from the center of the hurricane, showing how strong this storm is.
Reports of damage in Lake Charles include damage to hotels, skyscrapers and to the Golden Nugget Casino.
3:25 a.m.: Extreme wind warning extended, storm surge reaches 9 feet
Hurricane Laura is still a Category 4 storm as it batters Lake Charles, Louisiana, early Thursday with winds up to 132 mph.
The extreme wind warning in the area has been extended until 4 a.m. Lake Charles has seen sustained winds of 100 mph for almost an hour.
A storm surge of more than 9 feet is being reported in Calcasieu Pass, Louisiana.
Houston ABC station KTRK has reporters on the ground showcasing the strong winds in Lake Charles as the eye approaches.
2:49 a.m.: Thousands already without power as Hurricane Laura hits Gulf
As of 2:30 a.m. Eastern Time, more than 129,000 customers are without power in Louisiana and Texas due to Hurricane Laura. In Louisiana, there are at least 109,811 customers with no electricity and 19,270 in Texas.
As the storm moves north, a tropical storm warning has been issued as far north as Arkansas and a flash flood watch has been issued for Oklahoma, Arkansas and Tennessee.
The National Hurricane Center said Laura made landfall as a Category 4 hurricane, with maximum sustained winds of 150 mph and minimum central pressure of 938 millibars. The weather service said the potentially catastrophic impacts would continue.
The northern eyewall is moving over Cameron Parish, Louisiana. Lake Charles is currently seeing wind gusts of 128 mph.
2:05 a.m.: Hurricane Laura makes landfall in Louisiana
Hurricane Laura slammed into Cameron, Louisiana, bringing with it extreme winds, flash flooding and a catastrophic storm surge.
The hurricane is currently 30 miles south, southwest of Lake Charles, Louisiana. Laura is moving north at 15 mph, where winds are still reaching 150 mph.
Forecasts show up to 20 feet of storm surge is expected. That could go up to 40 miles inland in parts of the Southern Louisiana Coastline -- a catastrophic forecast.
"The eyewall of Laura is moving onshore over southwest Louisiana. Take cover now," the National Hurricane Center said in its forecast at 1 a.m. Central Time. "Treat these imminent extreme winds as if a tornado was approaching and move immediately to the safe room in your shelter. Take action now to protect your life."
There have been two reported tornadoes due to this storm.
ABC News' Jamie Aranoff, Max Golembo, Will Gretsky, Rachel Katz, Joel Lyons, Kelly McCarthy, Janice McDonald and Samantha Wnek contributed to this report.