Morgan Lake swam to survival after her car crashed off the Chesapeake Bay Bridge on July 19. Video shows the 22-year-old clinging to rocks underneath the bridge while she waits to be rescued. (Courtesy of Scott Fortney)

Scott Fortney was headed to the Eastern Shore on Friday to join his family at their house in St. Michaels, Md., when the tractor-trailer in front of him struck a Chrysler Sebring and sent the car over the side of the Chesapeake Bay Bridge.

Fortney stopped, rushed to the guardrail and watched in amazement as a woman swam to safety, eventually pulling herself onto a pile of boulders at the base of the bridge.

And then, Fortney began recording on his smartphone, documenting Morgan Lake’s survival after her car plunged into the bay.

Fortney posted the video on YouTube on Tuesday evening, adding riveting audio and visual details to an already remarkable story. On Wednesday, the National Transportation Safety Board announced an investigation into the incident, which captivated the country by combining a nightmare scenario with human triumph.

“She’s alive, and that’s an absolute miracle,” Fortney said in an interview. “I was shocked to see her on the rocks.”

Morgan Lake, whose car plunged several feet from the Chesapeake Bay Bridge, is seen Monday in Dunkirk, Md. (Marvin Joseph/The Washington Post)

Fortney, an Alexandria real estate broker, did not capture the crash — or splash — on his smartphone. His 21 / 2-minute video shows the immediate aftermath: Lake on the rocks, alive, with people calling to her from more than 25 feet up.

“Hang on, we’ve called 9-1-1! Hang on, they’re coming! They’re sending help!” a man shouts.

“There’s nobody else there, is there?” a woman asks.

“No,” Lake says.

“Can you come up a little bit more?” a man says, trying to coax Lake all the way out of the water.

Somebody asks her name.

“My name is Morgan Lake,” she says.

“Morgan, hang on! Help is coming, okay?” a man says. “You’re going to be fine. You’re fine. Here’s the ambulance, I can hear them. They’re coming!”

The scene was “surreal,” Fortney said. “It was just so unbelievable.”

He put the video clip online after returning from St. Michaels, where he didn’t have WiFi access.

Lake had a visceral reaction upon viewing the video, her father said. “It was a little upsetting; it was a little bit much,” said Marcelino Lake, who was unhappy that the footage was shared with the public. “I think the family should have been notified, and we were not.”

Fortney had just begun the bridge crossing Friday when the ordeal began. “I looked up to a series of very swift brake lights, everybody jammed on the brakes, and then I saw her car bounce off the side rail and go up over the rail,” he recalled. “There was a point where the car could have fallen back down onto the bridge, but it went over.”

When Lake’s vehicle fell into the bay, “everybody just jumped out of their cars. I ran to the rail, and she had just emerged from underwater. She was 10 to 15 feet away from the rocks and swam to safety.”

One of the Chrysler’s wheels was visible from the bridge “about a foot under water,” Fortney said, “but it was a pretty good distance away from where she swam.” There were no boaters nearby, no emergency vehicles within earshot — really very little sound at all, he said.

“It was eerie,” he said. “Just waves lapping against the rocks.”

Moments earlier — before he began recording — “there were a number of people crying hysterically on their cellphones.” They didn’t know whether the driver had survived.

By the time Lake, a 22-year-old College of Southern Maryland student, reached the rocks, Fortney said, “she seemed to be very level-headed. She was having good dialogue with people near me.”

Jumping off the bridge to help didn’t make sense, he said. Lake had told the other people that she had been alone in the vehicle, and she was out of the water.

“It didn’t seem that anybody could really do a whole lot from up top,” Fortney said. “She already seemed to be in a safe position, so why risk it? Had she not been so heroic by saving herself, the thought absolutely crossed people’s minds that we’d need to jump in to save her.”

Within minutes, a recreational boater stopped near the rocks to watch over Lake until rescue personnel arrived. Police soon poured onto the bridge as well. Fortney was too preoccupied with Lake, he said, to notice where the tractor-trailer’s driver was.

The driver of the truck, Gabor Lovasz of Canada, was not injured. No charges have been filed, but an investigation is continuing, according to Maryland Transportation Authority Police.

The NTSB’s Office of Highway Safety is sending two investigators to Maryland on Thursday “to determine if there are any new safety issues or potential recommendations the NTSB can make to improve bridge and highway safety,” a spokesman said. The auto group AAA Mid-Atlantic has raised questions about the safety of the Bay Bridge guardrails.

“That truck hoisted that car so far up in the air — heck, from what I saw, if that wall were higher, it may not have made much of an impact,” Fortney said. “I’m not as concerned with the wall height as I am with people driving safely.”

Eventually, he said, police cleared the road, sending cars that were behind the accident back down the bridge and diverting them to the other span, which then carried two-way traffic. Fortney resumed his drive to St. Michaels, but not everybody continued the trip east. “I witnessed some drivers just leaving,” he said.

“I wanted to join my family, get hooked back up with them; I wasn’t scared. But I was in a daze after seeing what I’d seen. . . . I was in a state of amazement of how easily it could have been me.”