Floodwaters in Louisiana have begun to recede, but the horror of the disaster continues to mount: on Wednesday afternoon more than 30,000 people had been rescued from the flood, 40,000 homes were affected and 6,000 people remained in shelters. At least 11 people have died.



Louisiana floods: state begins recovery from devastating storm – in pictures Read more

As some residents get a first glimpse of their destroyed homes, reunite with loved ones and connect with friends via social media, the scale of the trauma is coming into view. The American Red Cross reports that the flood is the worst natural disaster to hit the United States since Hurricane Sandy in 2012.

“The Red Cross is mounting a massive relief operation, which we anticipate will cost at least $30 million and that number may grow as we learn more about the scope and magnitude of the devastation,” Brad Kieserman, vice-president for disaster logistics for the Red Cross, said in a statement.

Facebook Twitter Pinterest Travis Guedry and his dog Ziggy glide through floodwaters keeping an eye out for people in need on Wednesday in Sorrento, Louisiana. Photograph: Joe Raedle/Getty Images

Barack Obama has declared the flood a major disaster, with 20 of the state’s 64 parishes damaged. Scattered reports of looting have emerged, and Governor John Bel Edwards said some parishes will enforce curfews at night. And the floods could have an impact well beyond the region; Exxon Mobil Corporation slowed production at its Baton Rouge oil refinery, the fourth-largest refinery in the US.

The rainstorm was just that – rain – and so it crept up on residents without the alarms and warnings that accompany a hurricane. It began in the Florida panhandle and worked its way west along the gulf coastline, never swerving south to gain strength in the gulf, and never turning north to die over land. Eventually it came to a stop over south Louisiana and gushed rain for days, sometimes at a rate of three inches an hour.

Southern Louisiana is a flat, low-lying plain so there was nowhere for the water to go; once the rivers filled, the water went cascading across the landscape, sometimes rising a foot an hour as people scrambled to keep their children and pets safe.

As the floods sneaked up on residents, they did likewise to the national consciousness. Charities and media organizations are mobilizing now, but locals say that for days they felt abandoned by a country distracted by political turmoil.

“This event doesn’t serve an entertainment purpose or make a political statement. It doesn’t pit liberal against conservative, black against white, it doesn’t showcase incompetence of government or a president’s lack of compassion or caring about a particular race or class,” said Julie Ralph, who lives in Saint Francisville.

Ralph started her own relief campaign, creating a shopping list on Amazon where people can buy necessities – toothpaste, soap, toilet paper – and have it shipped to her home in Saint Francisville, from where she has been driving throughout the flooded areas to deliver the supplies. “People keep saying it’s like Katrina but it’s not. I grew up with hurricanes and you at least have some warning. With this, there was none. People didn’t even have time to get their shoes,” she said.

That self-reliance also took the shape of what local people are calling the “Cajun Navy”, an armada of boats belonging to local hunters and fishermen. They used social media to coordinate and in the first few days of the storm they rescued tens of thousands of people stranded in homes and cars. As more official rescue groups arrived, they encountered resentment when they told the locals their services were no longer needed.

Facebook Twitter Pinterest Barbara Hart dumps water out of kitchen containers while trying to salvage belongings after flooding in Walker, Louisiana. Photograph: Brendan Smialowski/AFP/Getty Images

“Attn Cajun Navy I love y’all and appreciate everyone answering the call and heading towards the water,” one of the local organizers, Jared Serigné, wrote on Facebook. “Unfortunately we did not get an official statement on whether our help is needed or not. At this point I do not recommend assembling large groups and heading into flooded areas. From all accounts, you will just get turned away.”

Even so, the head of the Federal Emergency Management Agency (Fema), W Craig Fugate, said at a news briefing on Tuesday evening that help was on the way for the 60,000 people who have registered for Fema assistance.

“Irregardless of what it may be getting in the national coverage, we know this has been a significant impact here in Louisiana,” he said.