AUSTIN, Texas — The first mandatory evacuations of the Houston area were ordered early Monday morning, four days after it was first clear Hurricane Harvey would drown America’s fourth-largest city.

What is now Tropical Storm Harvey dropped more than two feet of rain on Houston in 24 hours before a brief pause Sunday. The storm is expected to move back into the Gulf of Mexico, recharge, and dump more rain onto Houston by Wednesday. Fifty inches of rain are expected in some areas by the end of the week.

Already the storm has killed six people, rendered thousands homeless, and trapped 7 million people, one-quarter of Texas’ population, in a federally designated disaster area.

Officials in Harris and Fort Bend counties told some residents Monday morning to leave ahead of imminent flooding. The Brazos River southwest of Houston is expected to swell to 60 feet and overtop levees. There are fears the levees may fail, in a repeat of New Orleans after Hurricane Katrina. Meanwhile, people living downstream from reservoirs designed to protect downtown Houston from flooding have been told to prepare for the controlled release of water by the U.S. Army Corps of Engineers to relieve pressure on dams.

When the storm previously known as Hurricane Harvey made landfall Friday, it was the strongest storm to batter the U.S. coast in 13 years and the worst to hit Texas since 1961.

Texas Gov. Greg Abbott told Houston residents that even in the absence of an official evacuation order, “you need to strongly consider evacuating.”

But there was immediate pushback from Houston officials, who said they knew better.

Harris County’s emergency management spokesperson, Francisco Sanchez, responded to Abbott’s suggestion on Twitter this way:

“Local officials know best. Houston has no evacuation order. In Harris County: very limited to select communities. LOCAL LEADERS KNOW BEST.”

One person tweeted back, “You’re going to feel stupid if this storm proves you wrong.” Sanchez replied: “Actually we feel quite blessed. And, thankful for the first responders & public safety officials that are working to keep us safe.”

Houston Mayor Sylvester Turner said on Friday that evacuation was not necessary.

“There are a number of people who are in Hurricane Harvey’s direct path, and evacuation orders have been given to them. But for the Houston area… this is a rainmaker for us. There’s no need for people to be thinking about putting themselves in greater danger.”

Harris County Judge Ed Emmett said the safest thing for Houston residents was for them to “stay where you are and ride out the storm… We don’t anticipate any kind of massive evacuation.”

Now it’s too late to leave the city, with almost every roadway in and out closed. Even Sanchez admitted as much on Twitter: “I can keep telling you to stay put, but the reality is YOU CAN’T GET ANYWHERE RIGHT NOW.”

More than 250 highways in Texas are closed, Abbott said.

Turner defended the decision not to evacuate Sunday, saying, “You can’t put 6.5 million people on the roads,” referring to the population of the metro Houston area.

Kathleen Blanco, who was Louisiana’s governor during Hurricane Katrina, told The Daily Beast on Sunday that an advanced plan on how to evacuate the most susceptible to flooding is what was needed.

“It’s not apparent to us watching that they have developed a sensible evacuation formula,” she said. “You have to allow people in the southernmost regions to get out the quickest. You can’t tell everyone to leave at the same time or you end up with gridlock, especially in a big urban center.”

Blanco said 1.3 million people were evacuated from the New Orleans area before Katrina hit. (She was criticized for rebuffing the Bush administration’s request to federalize the evacuation of New Orleans after Katrina made landfall.) That same year, Houston ordered evacuations for Hurricane Rita, putting 2.5 million people on the roads. More than 100 evacuees died.

“I was just talking today with relatives there in Houston because I was concerned about them,” Blanco said. “They said they were not going to evacuate again because during Rita they got a few blocks from their home and couldn’t get up on the interstate. Just traveling those few blocks took 12 hours because of the gridlock.”

Regardless of the wisdom of evacuation for Harvey, it should’ve been clear Houston would flood.

Meteorologist Eric Holthaus told The Daily Beast that by midday last Wednesday there had been “pretty compelling model agreement on major flooding” and that the “upgrade in forecast to major hurricane on Thursday morning, I think, made most meteorologists absolutely convinced.

“Keep in mind, though,” he added, “there’s never been a mandatory evacuation based on a rainfall forecast, so I’m not sure that people even knew what to do with a forecast as dire as this one.”

Houston was a sitting duck for the next big hurricane, as ProPublica reported last year.

“Unchecked development is wiping out the pasture land that once soaked up floodwaters,” ProPublica reported. “Houston’s rapid expansion has greatly worsened the danger posed by flooding.”

Ironically, refugees driven from New Orleans by Katrina in 2005 ended up in the Houston Astrodome, where Sanchez had his first experience with emergency management communications.

“When it comes to alerts and warnings, it’s something that to me is very important personally,” Sanchez told said in an interview last year. “When you’re put in these sorts of positions, you have that responsibility.”

Blanco, who did not run for re-election following Katrina, said it’s a no-win situation, with millions of lives at stake, few resources, and little room for error.

“There is always a lot of finger pointing, even when it’s semi-successful,” she said. “A disaster creates a situation people find untenable and the citizenry suffers, and they want someone to blame.”