Through Monday morning, Harvey continued to unleash record levels of rain on Houston, causing “catastrophic” flooding in the city and in surrounding Harris County, where at least six people appear to have died as a result of the storm.

Some parts of Harris County have received more than 30 inches of rain since Friday, according to the National Weather Service. The NWS warned of “additional catastrophic, unprecedented and life threatening flooding” through this week and placed flash-flood emergencies for all of Southeast Texas.

As the much-anticipated storm pummeled the country’s fourth-largest city — overwhelming the 911 system and sending some residents, against the advice of officials, into their attics to flee floodwaters — many asked the question: Should Houston have been evacuated? If so, why wasn’t it?

At least one top official thought it should have been.

On Friday, before Harvey made landfall, Texas Gov. Greg Abbott (R) encouraged residents to evacuate low lying and coastal areas, even if a mandatory evacuation order had not been issued.

“Even if an evacuation order hasn’t been issued by your local official, if you’re in an area between Corpus Christi and Houston, you need to strongly consider evacuating,” Abbott said at a news conference. “What you don’t know, and what nobody else knows right now, is the magnitude of flooding that will be coming.

“You don’t want to put yourself in a situation where you could be subject to a search and rescue.”

The governor’s warning was in sharp contrast to the advice local and county officials had been dispensing for days: Shelter and stay in place.

And it set off a scramble by local officials on social media to tell Houston-area residents otherwise.

“LOCAL LEADERS KNOW BEST,” Francisco Sanchez, spokesman for the Harris County Office of Homeland Security and Emergency Management, tweeted in response to Abbott’s warning.

There were no evacuation orders in Houston, and orders only existed in a few communities in Harris County, Sanchez stressed on Friday afternoon.

In a follow-up tweet, Sanchez urged residents to heed the advice of local officials, such as Harris County Judge Ed Emmett and Houston Mayor Sylvester Turner, rather than the governor.

On Saturday morning, as Hurricane Harvey’s powerful winds and rain caused severe damage to coastal communities, the Houston mayor warned people there would be heavy rain and flooding in the city for the next four to five days — but once again emphasized they did not need to evacuate.

Turner also addressed concerns that Abbott and local officials had sent conflicting messages about what was safer: fleeing or staying in place.

“Quite frankly, leaving your homes, getting on the streets, you’ll be putting yourself in more danger and not making yourself safer,” he said. “And so, we’re just asking people to hunker down.”

The following day, as the storm’s devastating toll came into better focus, Turner defended his call for people to stay in place.

“There was a lot of conversation about the direction in which hurricane Harvey was going to go,” he said at a news conference Sunday. “No one knew which direction it was going to go. So it’s kind of different to send people away from danger when you don’t know where the danger is.”

He added that trying to evacuate the city in such a short time would have been logistically “crazy,” as history has shown.

“Remember the last time we evacuated, there was a great deal of confusion, great deal of chaos,” the mayor said. “There were people that were going to Austin that were on the road 10 to 12 hours, if not longer. There were people who ran out of gas on their way — a great deal of confusion.”

Turner was referring to the city’s evacuation ahead of Hurricane Rita in 2005, a disastrous effort that resulted in dozens of deaths and widespread criticism of the authorities.

Emmett, Harris County’s chief executive, echoed Turner’s thoughts Sunday, telling reporters there was “absolutely no reason” to evacuate the city before the storm.

“You cannot put, in the city of Houston, 2.3 million people on the road. … That is dangerous,” the judge said, according to CNN. “If you think the situation right now is bad — you give an order to evacuate, you create a nightmare.”

And during a record breaking flood, one expert said, inside a car is one of the most dangerous places to be, which complicates the decision to evacuate.

“People disproportionately die in cars from floods, so evacuation is not as straightforward a call as seems,” Marshall Shepherd, a program director in atmospheric sciences at the University of Georgia, tweeted Sunday.

Still, reports and images from Houston and Harris County showed it was increasingly difficult for people to stay off the streets.

As The Washington Post reported, Texas officials had begun to get a sense of the full magnitude of the storm, including its effect on rivers and levees

The Brazos River, which runs southwest of Houston, is expected to reach record heights in the coming days. National Weather Service models showed the river rising to 59 feet by Tuesday, topping the previous record of 54.7 feet.

“A flood of this magnitude is an 800-year event, and it exceeds the design specification of our levees,” Fort Bend County Judge Robert Hebert said in a statement Monday.

The National Weather Service — which tweeted the “beyond anything experienced” description that morning — was predicting that parts of Texas could receive nearly 50 inches of rain, the largest recorded total in the state’s history.

FEMA Administrator William “Brock” Long said Monday that Harvey could force 30,000 people into shelters, and he anticipated 450,000 people would seek some sort of disaster assistance.

“We have not seen an event like this,” he said. “You could not draw this forecast up. You could not dream this forecast up.”

[Trump praises storm response as millions brace for historic flooding]

Houston and Harris County officials who urged people to stay home before the storm may have been remembering that the city government was strongly criticized after the disastrous evacuation before Hurricane Rita in 2005.

In the hours before Rita struck the Houston area in September 2005, government officials issued an evacuation order, and some 2.5 million people hit the road at the same time, according to the Houston Chronicle.

Officials later reported more than 100 deaths connected to Hurricane Rita — and at least 60 of those deaths were linked the evacuation itself, according to a 2006 report to the Texas House of Representatives.

Dozens were injured or died of heat stroke waiting in traffic for nearly a full day. Fights broke out on clogged highways. A charter bus carrying people from a nursing home exploded on the side of Interstate 45, killing 24 people inside.

Meanwhile, the fear from Hurricane Rita turned out to be unfounded. It weakened from a Category 5 churning in the Gulf of Mexico to a Category 3 by the time it made landfall in East Texas — and resulted in a fraction of the damage and deaths as Hurricane Katrina, which had ravaged New Orleans three weeks earlier.

After Hurricane Rita, many in Houston returned to their homes after hours of languishing on the highway “and found the house was fine and the street wasn’t flooded,” according to Madhu Beriwal, the president and chief executive of IEM, a disaster planning and prevention company who has worked in Harris County. Her company wasn’t involved in planning for Hurricane Harvey, and she said she did not advise officials about whether to evacuate the city.

In evacuation planning, public officials are trying to find “the course of least regret,” Beriwal said. Traveling by car has inherent risks, and any mandatory evacuation order comes with the grim understanding that people will die trying to get out, she added.

“We know that there’s going to result in a certain number of deaths just by having so many people on the road,” Beriwal told The Post. “When you have evacuation traffic, it’s even more difficult, because you have people that are very vulnerable traveling. … The people that tend to die in bigger numbers (during evacuations) are generally the elderly — people that wouldn’t normally be on the road anyway.”

But no matter which path officials decide to take, Beriwal said, “It is always better to speak with one voice so people know what the officials think is the best thing to do.”

After Rita, officials began changing laws and government programs to improve future evacuations.

The state’s emergency management division began to work more closely with municipalities to coordinate hurricane response plans, the Texas Tribune reported, “including finding ways to restore power sooner.”

Lawmakers amended statutes to make it easier for emergency workers from other parts of the state to help during a crisis, the Tribune reported, and removed liability worries that hindered mutual aid.

Now, state and local authorities participate in drills to reverse the traffic flow on the highway to “ensure various agencies stay familiar with the process.”

On Monday, Houston Police Chief Art Acevedo was asked by a Fox Business Network anchor whether it was a mistake not to order an evacuation ahead of Harvey.

“Oh lord, you know I love the backseat quarterbacks,” he said. “I absolutely support the decision of our mayor and the county judge to not evacuate. Where do you take … 6.5 million people, where do you send them? Especially in a state that is so prone to flash floods on our highways, we haven’t been able to get resources here because highways have been blocked throughout the state of Texas.

“So I don’t think they understand the complexity, they don’t understand just how widespread this entire emergency has been.”

Texas State Rep. Armando Walle, who represents a district that stretches from northern reaches of Houston into unincorporated parts of Harris County, told The Post on Monday the decision against ordering evacuations probably saved lives.

“You would have had a calamity of biblical proportions; that’s not an overstatement,” he said. “If you put 1 million cars on the road when every major road in this region is under water, it would have been a disaster. There are challenges in any disaster, but that decision not to call for mandatory evacuations was the right decision. I believe that you would have had thousands of people perish. … People have listened to their local leaders and are paying attention.”

♦ Culled from the Washington Post