Francine has weakened to a tropical depression after slamming into Louisiana as a Category 2 hurricane and leaving widespread power outages in its wake.

On Thursday, authorities in the United States warned of “life-threatening” storm surges as Francine moved over the neighbouring southern state of Mississippi. Heavy rains and possible flash floods were forecast across Arkansas, Tennessee, Alabama, Georgia and Florida.

The National Hurricane Center warned that residents in coastal Louisiana and Mississippi “should follow advice, including evacuation orders, from local officials”.

At least 10 parishes had ordered evacuations in Louisiana as the storm travelled parallel to Texas in the Gulf of Mexico before making landfall in Terrebonne Parish on Wednesday. It brought 155-kilometre-per-hour (100-mile-per-hour) winds, making it a Category 2 hurricane on the Saffir-Simpson wind scale, which uses a rising 1 to 5 rating based on sustained wind strength.

Francine then headed northeast across New Orleans, battering the city with heavy rains.

Residents of the state woke up to scattered debris and some damage. Governor Jeff Landry said the National Guard would visit impacted parishes, bringing food, water, almost 400 high-water vehicles, 100 boats and 50 helicopters to conduct possible searches and rescues.

A police car drives past a fallen tree after Hurricane Francine hit Kenner, Louisiana [Matthew Hinton/The Associated Press]

While no deaths or injuries were initially reported, the storm brought several harrowing moments.

A television camera from the WDSU-TV station captured rushing water trapping a driver under an underpass in New Orleans. A nearby resident waded through the water to smash in the vehicle’s window and save the driver.

In low-lying Jefferson Parish, flooded streets were draining early on Thursday after authorities pumped water through the night, a local official said in a social media post. However, she warned of persistent problems with the sewer system.

“We are urging residents to continue to conserve water by limiting non-essential activities like washing dishes and doing laundry in an effort to minimize overloading the Jefferson Parish sewerage system,” parish President Cynthia Lee Sheng wrote on Facebook.

In Lafourche County, sheriff’s deputies helped evacuate 26 people, including several children, trapped by rising water, the sheriff’s office said in a statement.

More than 400,000 power outages were reported in Louisiana and Mississippi early on Thursday, according to a website that tracks power losses.

A mangled tree covers part of a street in New Orleans [Kevin McGill/The Associated Press]

Francine’s wind strength dropped to 56km/h (35mph) as it travelled over Mississippi at about 19km/h (12 mph) on Thursday, according to the National Hurricane Center. It was expected to continue to weaken as it moved over central and northern Mississippi through early on Friday.

Unusually warm waters in the Atlantic, caused in part by human-caused climate change, have made hurricanes in the region more powerful in recent years.

However, the 2024 hurricane season has so far been less severe than initially projected. Francine is only the sixth named storm of the season, which runs from June 1 to November 30.