They'd waited all week for it. And then finally, on the afternoon of Sunday, August 28, as Hurricane Irene began to ebb in the northeastern states it had ravaged, a group of rafters got their chance. Torrential rains had transformed the Croton, a mild river that flows through suburban Westchester County, into the sort of Class V thrill ride they’d fly across the country to paddle. Earlier that week, Dr. Peter Engel, a 53-year-old psychiatrist and addiction specialist who'd done some of the world's most challenging rivers, texted a friend, "Now that it’s all going to be flood, it's time to go boating."

That day the river, which runs over the spillway of the massive Croton Dam and continues for three and a half miles into the Hudson, was a hellbroth of logs, tree limbs, stumps, and whole trees that had been uprooted from the saturated banks. Normally, the river flows at 300 cubic feet per second; it was now running at 22,500, the heaviest in 55 years. Its currents had reached nearly 50 miles per hour (faster in more narrow chutes) and churned with colossal wave trains and Class V and even Class V–plus rapids – the kind of muscular surge you'd see in the Niagara River below the falls. Midstream, islands of rocks and trees had been almost completely submerged, creating classic "strainers," which whitewater riders avoid at all costs. "That river can be treacherous on any given day," Croton police detective Paul Camillieri says. "But that day it was a monster. It was Mother Nature at its most fierce and unpredictable."

The trip had been organized by 37-year-old Ken GiaQuinto, the business manager of a pharmacy his family owns in the city of Rye, New York. GiaQuinto had worked for a time as a river guide in Breckenridge, Colorado. The 12-foot blue raft was his. As Irene made her way up the eastern seaboard, Gia­Quinto sent text messages to four friends he thought might want to take advantage of the dramatic rainfall. One was Brian Dooley, a third-grade teacher who coached high school lacrosse with GiaQuinto and was celebrating his 33rd birthday that day. Another was Joe Ceglia, also 33, a boyhood pal of Dooley's who’d been a lacrosse All-American at Syracuse University and even played professionally. He was now the athletic director at Rye Neck High. Neither of them had done a lot of whitewater rafting. A third recruit was 37-year-old Michael Wolfert, an avid skier and climbing-school owner with considerable rafting experience. He lived about 100 yards from the Croton Dam gorge and was familiar with the Croton, at least under normal circumstances. The fourth friend was older and more seasoned than the others. Dr. Peter Engel, who had two adult children, had been running whitewater for more than 30 years. He was the last one to arrive at the river that day, rendezvousing with the other rafters at around 4 pm.

The crew had a hard time finding a safe put-in, so they drove to a county park beneath the massive Croton Dam, inflated their raft, and parked it on a bridge spanning the raging water below. GiaQuinto’s and Wolfert’s wives snapped pictures of their children in the boat, while the crew assessed the water from the bridge.

There were dozens of people in the park that afternoon, most gaping at the cataract crashing over the dam’s massive spillway. "Everyone seemed dumbfounded that anyone would try to do this," said Mark Stevenson, a photographer who shot footage of the group that day. But, he said, the group had an "air of authority" and all the right gear. At one point Stevenson asked GiaQuinto if they had experience with whitewater. "Oh, yeah," GiaQuinto joked. "We looked it up on Google."

Normally, rafters wouldn’t put a boat in the water until they'd had a chance to do a safety walk, scanning the river by foot to evaluate various hazards and plot their course. But the water level made a full survey impossible. And the doctor, the most experienced of the group, hadn’t had a chance to read the water features at all.

According to the American Whitewater organization, the Croton River can present rafters with a number of hazards: keeper holes, rocks that cause blunt trauma, natural strainers, and low-head dams that create unpredictable hydraulic perils. That day the five-man crew would encounter them all.

They launched late in the afternoon, around 5:30, but with near–50 mph currents, they knew they'd finish the trip well before dark. The first mile or so was fast but flat. They "smoothed" three low-head dams with ease, and then a higher, more difficult dam, in near-perfect form. GiaQuinto was sitting comfortably in the stern, calling out paddling commands. When they came upon a bridge that had 12 feet of clearance on a normal day, the rafters leaned backward in the raft to duck beneath it. A photograph taken from that bridge shows the crew beaming, thrilled at being on such powerful water.

Less than two miles downriver, the group hit a wave train that resembled a giant roller coaster, as well as a set of rapids. Then, not even 10 minutes into the trip, they rounded a bend into Silver Lake, a wide, flat part of the river used as a town swimming hole under usual conditions. At this point the rafters could have paused in an eddy by the riverbank to assess what hazards lay ahead or to consider altering their original course. The trickiest waters were still to come. If they’d wanted to pull out and call it a day, this was their last chance.

But they pressed on, and at the Silver Lake spillway, the boat skewed to the right and plunged into a lurking depression.

Immediately, the raft somersaulted, stern over bow. "Somehow we just hit the wrong spot at the wrong angle at the wrong time," Wolfert explained later. Another rafter subsequently told police: "We never thought an accident would happen. There was no notion of danger. All of a sudden, the boat just flipped."

Thrown into the smash and boil of the churning 70-degree water, Ceglia, the raft­er with the least experience, knew enough to keep his feet up and his head out of the water as he barreled through a half-mile of powerful rapids and rolling waves in a matter of minutes. He managed to grab onto a tree on the flooded right riverbank and cling to it until a Croton policeman and volunteer firefighters threw him a rope and pulled him to safety. "I’m OK," he told rescuers, "but I've got four friends still out there."

As Ceglia was speeding downstream, GiaQuinto and Wolfert struggled to swim out of the hydraulic backwash created by the underwater dam. GiaQuinto later told a friend it was the hardest swim of his life and that he thought he was going to die as the force of the backwash dragged him and his life jacket under. Somehow, both he and Wolfert made it safely to shore.

Dr. Engel had a more difficult ride downstream. He was found by a Croton police rescue boat at 6:24 pm, facedown in the water about a half-mile from the mouth of the Hudson. He still had on his dark-green helmet, his life jacket, and his dry top. But all of the garments on the lower half of his body — including his baggy Nike swim trunks — had been ripped off by the river or a strainer he might have passed through. According to the medical examiner, he had a laceration on his forehead and an abrasion on the bridge of his nose, as well as contusions, bruises, and scrapes all over the rest of his body. The official causes of death were asphyxia by drowning and hypothermia; his body temperature was 93 degrees at the time of his death.

Now four of the rafters were accounted for – Brian Dooley was still missing. As the sun was setting, dozens of responders fanned out along areas where Dooley – or his body – might be.

As soon as the call went out that a raft had flipped, local rescuers put their boats in and assumed shoreline watch posts. Croton’s volunteer fire department and EMTs were joined by counterparts from neighboring communities, county police, and emergency personnel; police helicopter crews came from as far away as New York City. More than a hundred personnel turned out to assist the rescue operation, several of them nearly becoming victims of the river that day, too.

Three volunteer firemen went swimming after launching an 18-foot skiff just above a railroad trestle bridge. Their engine stalled soon after they launched, and they could do nothing as an onlooker cried out, “Bridge! Bridge! Bridge!” The firemen’s boat capsized when it slammed against the railroad bridge, and the crew members were swept downriver. One of the three, the department's 44-year-old chaplain, found himself trapped under the boat, his foot snared in a line. He didn’t break to the surface until he was more than 200 yards out into the Hudson.

Geoffrey Haynes was at home, listening to his police scanner, when he heard about the missing rafter. The former AP reporter thought he might be able to be "another pair of eyes, if nothing else," in the Dooley search. He and his 23-year-old son grabbed life jackets and binoculars to scan the area where the raft had flipped. On their second sweep of the riverbank, the elder Haynes looked through his binoculars and spotted Dooley’s orange jacket and turquoise dry top about 30 yards from the river’s far bank at the upper tip of Fireman’s Island. He had wedged himself into a sweet spot in the nook of two trees, Haynes said, but the water was still crashing over him, pushing him into one of the trees, forcing him to constantly change his grip. "To get to this guy would have required a Navy SEAL operation," Haynes said. Dooley kept trying to pull himself up higher on the tree, reaching for a small branch above his head. But as the hours passed, his motions got slower as hypothermia set in.

A Westchester County Technical Rescue Team, trained in swift-water operations, put in a rescue swimmer, but he was immediately swept away and pulled from the river by teammates downstream. A helicopter rescue had been considered, but the tree canopy and the continuing high winds made it inadvisable to drop in a crew member on a harness. The only thing a helicopter could do was hold Dooley in its searchlights so rescuers could keep track of him.

Around 8:45 pm, Geoff Haynes picked up his binoculars to check on Dooley, but he was gone. A moment later he heard over the police radio that Dooley was out of the trees. Croton Detective Sergeant John Nikitopoulos and his two-man dive team had been idling in their Zodiac by the shoreline downstream. When they heard the radio chatter, they hurried out into the river. Using powerful handheld searchlights, they got a visual on Dooley, who was moving downriver at about 1,000 yards in 30 seconds. He flapped his arms weakly to signal them. When they hauled him into the boat, Dooley curled up in the hull, "totally spent," Croton police lieutenant Russel Harper later said. Dooley, who’d spent close to three hours of his birthday struggling in the water, was shaking and almost unable to speak. He was admitted to the hospital with extreme exposure and hypothermia. He told police he wasn't sure whether he had lost consciousness or lost his grip. He had no idea how long he'd floated or how he made it without hitting any trees.

The day after the incident was bell-blue and sunny, and a rainbow arced over the Croton River where the rafters had put in, but elsewhere in town, a stormy backlash was brewing. Some townspeople were furious that the rafters had put so many res­cuers at risk simply to satisfy what one called "juvenile urgings." The comments sections of local news sites teemed with ugly remarks. "Score one for Darwin," somebody posted. Another cracked, "Good riddance. Minus one arrogant, reckless soul in the world."

Not helping things were certain statements that survivor Michael Wolfert made to the press. "We were not novices," he told one reporter. And when asked whether they calculated the risks of rafting the swollen river, Wolfert replied, "It's a risk we assume." But the risks of their ride were hardly confined to the men in the raft. Three volunteer firemen and a rescue swimmer nearly drowned. Helicopters came and went in dangerous winds, hovering over a heavily treed gorge. Many in the town thought the rafters should have been billed for the rescue, estimated at more than $45,000; others urged criminal prosecution.

Engel's paddling buddies were left scratching their heads. "Peter was not reckless," insists lifelong friend Gary Maltz, an internist who’d paddled the Gauley with him. "When he went on a river, he usually knew every nook and cranny. He was very safety-conscious, very smart, very rational." But the crew had violated some of the cardinal rules of whitewater paddling. They had not done a full safety walk and had shot low-head dams that they might have portaged. Most significantly, they left no margin of error – for being stranded, caught in a strainer, snagged on a tree, or thrown overboard.

Maybe they failed to give a local, suburban river the respect they'd give rivers with bigger names, fiercer reputations. Croton detective Paul Camillieri thinks it was a case of hubris. "They thought they were going for a Sunday ride. That it'd be over quickly, they’d high-five each other and then go for beers. I don’t think they really took it seriously enough." Richard Charney, who'd paddled the Colorado and whose house is near where Ceglia was rescued, maintained that the big rivers Engel had done are "known quantities." Their features and hazards are studied and discussed by paddlers who'd done them. "But that experience would not apply to the Croton at that level," he says. "At that level, it is a completely unknown quantity."