Pastor Marty Murray, piloting an airboat, and his group of volunteers tie up to their truck after a rescue mission. (Lucian Perkins/For The Washington Post)

Marty Murray and his friends powered the airboat along the water, passing cars submerged to near invisibility in the darkness, until the airboat suddenly ran aground onto asphalt and into the flashlight beams of three men carrying assault rifles.

It was after 9 p.m. and the sky was dark, the waters darker, and the police had urged people not to do things like this. But Murray, 45, was determined to rescue people tonight; determined to heed the calls coming in over the ad hoc walkie-talkie system that volunteers like him were using to help the people he knew were stranded out there in the darkness. And he had just driven three hours from New Caney. He wasn’t going home empty-handed.

“I gotta go to 61st Street to get a woman and a dog,” he said, stepping out of the airboat and staring at the armed men.

Murray, a small-town church pastor and businessman by day, is among the hundreds or even thousands of ordinary Texans who have been transformed overnight — with the force of a flood, the blessing of some boats and no small dose of courage — into men with a higher purpose.

And so it was that on Wednesday night, after two days of rescuing flood victims in the small towns north of Houston where he lives, and after driving three hours east in pursuit of the moving storm and more rescues, Murray and his friends wound up in this devastated town on the Louisiana border, face to face with other ordinary men like them who also came to help.

Murray, an imposing man clad in camouflage rain boots, didn’t like the fact that the men had guns, especially not with fears of possible looting coming in over the radio. “What are you doing?” he said, scowling at the men, who approached slowly under the orange glow of a street lamp. “You’re going to scare people.”

As they drew closer, the rifle-bearers turned out to be in their teens or early 20s, one wearing a Batman T-shirt and another a shirt that said “USA Proud.” They brought the guns for protection, they said mysteriously, because people are robbing people.

“We got reports that there were 60 people over here robbing people,” Murray responded. “I said, ‘I don’t care.’ ” There were people who needed rescuing, he added, and he had heard over the radio that there were 10 children nearby in need of an evacuation, as well as a woman and her dog.

A couple other volunteer rescuers — Brian Jamar, who runs an air conditioning company, and Josh Franqus, who works in septics — had by that point wandered over, too: They had responded to the same call. But they had been searching the area for hours and couldn’t find any kids in need of rescue.

“I’m pretty sure it was a bogus call,” Jamar, 29, said.

Murray persuaded a few of the others to join him and his friend for one last search anyway, and soon they were speeding off on another man’s truck toward the address other volunteers had given them.

Murray and his group of volunteers wait for a call to take their boat in for a rescue at a staging area in Beaumont next to a Waffle House. They soon received a call to rescue a woman and a dog and 10 children trapped in an apartment. (Lucian Perkins/For The Washington Post)

They get an adrenaline-pumping thrill from these rescue calls, relayed over a phone app called Zello that enables ordinary people to play the role of emergency first responders, using words like “roger” and “copy that” as they report on rescues needed or undertaken.

Kristy Davis, a special agent with the Texas Department of Public Safety, who works in the cluster of towns north of Houston where Murray lives, credited the volunteers in that area with rescuing at least 500 people in three days this week.

At improvised “staging grounds” in other neighborhoods around Houston, volunteers and sheriff’s deputies have met and traded information. At one gas station in Cypress, where the Harris County Sheriff’s Department showed up Tuesday to register volunteers and their boats, several dozen eager would-be helpers packed into the parking lot with everything from deep-water fishing boats to sea kayaks and water skis in tow.

“The response was overwhelming,” said Sarah Malkowsky, a spokeswoman for the Harris County Sheriff’s Department, who said hundreds more turned up at a department training facility where they registered more people. “The hardest part was each one having to wait their turn. Some weren’t given an assignment right away and they left to find [rescue] work through their own means.”

Some even showed up without boats. “Anyone need an extra hand for their boat?” one man called out at the gas station as a sheriff’s deputy took down volunteer information.

All over Houston and nearby towns, trucks with boats have become a common sight, often driving directly toward the rising flood waters, as Murray, his friends and a snaking line of nearly a hundred other such volunteers did Wednesday night en route from Houston to the Louisiana border. Even as local police have issued stern warnings that residents who ignore mandatory evacuation orders will not be rescued, these men might show up anyway.

The outpouring of help has yielded no small degree of chaos in its own right. “It’s like when a shelter asks for supplies and the next thing you know, you’ve got a million bottles of water you don’t know what to do with. With the volunteers, we were inundated,” Davis said.

“It’s helpful,” she added. “But there are people who are doing it who have never been trained, and their boats are overturning and we have to rescue them.”

The emergence of free-for-all amateur walkie-talkie networks has also given way to a flood of false claims and rumors, some the results of mass confusion and poor coordination among volunteers, and others the products of pranksters.

The day before he headed to Port Arthur, Murray and a couple dozen of his congregants who had gathered at the church to assist with rescues had been listening intently to all the walkie-talkie chatter and doing their best to respond.

There were urgent calls for rescues at a hotel and apartment complex in Katy, west of Houston, where the water was rising fast. There were warnings of an imminent explosion at a chemical plant in Conroe. And there was the never-ending stream of individual messages: the woman whose mother desperately needed blood pressure medication; the child and his family allegedly trapped on a rooftop; the old man in the attic; the woman who hadn’t been heard from in days.

“Hi ma’am? Yes, our rescuers are out in the area. Is there any way you could get ahold of your mother?” a teen church volunteer in a pink shirt said into the phone at one point, as another woman scribbled addresses and updates on a whiteboard. “Our guys are circling around, they can’t find the house,” the teen pleaded. “We need her to come outside or something so they can figure out where she’s at.”

Murray, whose own home had flooded, and whose wife and three children were waiting out the flood at a friend’s house on higher ground, was running on three hours of sleep. But he felt pride and purpose in coordinating such a mission. By Wednesday, he estimated that he had helped more than 30 people get to safety.

“This is the community,” he said, as he surveyed the parking lot of his small church, where he and his congregation had successfully created a launching point for area rescuers. There were fishing and leisure boats, airboats, jet skis and johnboats. In his church lobby, a mass of strangers in camouflage and waders stood around chomping on ham sandwiches, airing the odor of damp feet as they changed into dry, donated socks, and turning to Murray for orders.

“Is there anywhere we can go right now?” a man in beige waders asked, as Murray directed his own voice to the airwaves: “Does anyone need boats in New Caney?”

But not all the rescues were successful: There were dozens of times that the rescuers showed up — sometimes braving treacherous currents and unpredictable water levels — to find no victims in need of help.

“It’s so busy that people are reaching them and no one is ever getting on there and saying, ‘We got them,’ ” Murray said at one point. “It’s emotional. You’ve got pandemonium.”

Other times, the help that was “needed” turned out to be less urgent: a cat in an empty house or a man who probably could have walked to safety in ankle-deep water. And then there were the more curious cases of those who didn’t want to be rescued at all, such as the drunk woman in the flooded home who tried to fight off the men responding to the rescue request made by her concerned daughter, or the old man in the attic who didn’t want to leave without his 17 dogs.

(That one prompted Murray to get on the phone: “Either my guys get you, or the constables are going to come in and get you,” he warned. “My guys put their lives at risk to come in and get you, brother, and we need you to come out of there.”)

In the darkness of Wednesday night, after chasing a storm that had moved east, three hours from his home, Murray was facing the real possibility that there would be no successful rescue here to feel good about.

There were some horses on a traffic median, and some dogs on a balcony, but the 10 children for whom the anonymous dispatchers had pleaded were nowhere to be found. If they existed at all, they probably had been rescued hours before.

“Man, I am so sick of people not being there,” he exclaimed.

But there was one rescue: A 22-year-old in plaid pajama bottoms who had been stranded at a friend’s house. “We need to get this man to the hospital,” Murray announced as he powered up the airboat’s roaring propeller, the young man climbing aboard.

Murray is thanked by a young man whose mother had called in to say he needed to be rescued from a friend's house. (Lucian Perkins/For The Washington Post)

It turned out the man, a college student who gave his name as Robert, was fine. His friend’s house, though isolated by nearby floodwaters, was never damaged. But his mother, who works at the hospital, wanted him home, he said. “I guess my mom was worried and asked them to get me,” he said sheepishly.

Motoring back down the dark expanse of water, past the submerged cars, the airboat’s exhaust pipe suddenly snapped, as did the rudder. The boat briefly lost control, nearly hitting a mailbox and a car.

The water was shallow enough, so the men walked the rest of the way to dry pavement; Robert in his pajamas, the murky water up to his calves.

After depositing their rescue at the hospital, Murray and his friends conceded that he would be their only one in Port Arthur. The boat was inoperable, and one of the men had to get to his job working on refrigeration trucks back in New Caney the next morning.

There were still calls coming in over the walkie-talkie, and still more potential rescues out there in the darkness that Murray wished he could get to.

“It sucks to come all this way,” he said. “But at least we got one person. So we didn’t come out here for nothing.”

That near-miss with the mailbox out in the water was pretty crazy, too, his friend John Peters added.

“Did you see me slide all the way over to the bridge to get out of the way?” Murray responded, as the men started laughing. They had to admit, this work was also kind of fun.

Murray and his group of volunteers end their night after returning on their damaged boat to their truck. (Lucian Perkins/For The Washington Post)