Johnny Marcano was on the 10-minute drive Tuesday afternoon from his uncle’s home in Dorchester to his own place in Roxbury when he started to ease his Honda through an underpass. That’s when the water started rushing in.
“A smaller car had just driven ahead,” Marcano said, “and the water didn’t look that deep.”
But it was.
And soon enough, Marcano, his vehicle sodden and stranded, found himself among many across Boston on Tuesday who found their streets flooded and their commutes brought to a halt in gridlocked traffic after 2 inches of rain poured down swiftly and ferociously in the afternoon.
Charlie Foley, a National Weather Service meteorologist, said parts of Dorchester — near where Marcano had his watery encounter, at Quincy and Ceylon streets — were under 3 feet of water.
The Boston Water and Sewer Commission had 29 calls reporting street flooding in Dorchester, Hyde Park, Roxbury, and other low-lying parts of the city, said Danielle Domingos, a commission spokeswoman.
She said crews were dispatched to trouble spots to make sure storm drains were clear throughout the day. The spot where Marcano was flooded out, she added, is a chronic problem. “That’s the lowest spot in the city,’’ she said. “We are always having problems there.”
The city was knotted in traffic as police worked to divert commuters around flooded roads. Portions of Columbia Road near where Marcano stalled were still blocked off about 2 p.m. while city workers drained stubborn puddles.
“We’re having weather-related delays all over the city due to significant flooding, and ask that people exercise some patience and give themselves extra time [to drive],” said Boston police spokeswoman Cheryl Fiandaca.
Department of Transportation spokesman Michael Verseckes said that although there were no reports of major accidents Tuesday, traffic volume on Interstate 93 was heavy in both directions because of slow speeds and heavy rains.
On Beacon Hill, Charles Street quickly became a paved version of its neighbor, the Charles River.
“There was a small river going down the street, but it wasn’t anything too scary,” said Erin Ellis, an employee at Black Ink. She said the water in the street was 4 or 5 inches deep.
Betsy Daly, 57, had to have her car towed Tuesday because it had flooded. She was parked on Charles Street, and when she returned to her car, she noticed it was surrounded by 4 to 6 inches of water on the sidewalk and was filled with 2 to 3 inches of water inside, she said.
The water must have shorted the car’s electrical system, Daly said, because when she sat down in the driver’s seat, it started moving forward without warning, and didn’t stop until she sat wedged between the seat and the steering wheel.
“I was almost crushed,” she said. “I didn’t know what a flash flood meant until today, but now I know. What a nightmare.”
In Hyde Park, Melissa Martinez, a worker at the Stop & Shop on Truman Parkway, said customers were complaining about 2 feet of water outside.
Rain was heaviest Tuesday in Acton, Carlisle, and Littleton, according to National Weather Service spokesman Bill Simpson. He said two clusters of thunderstorms marched through Greater Boston, the first starting about noon and the second about 3 p.m.
Lightning struck four houses in Bellingham, damaging one severely, according to authorities.
Storms toppled two large trees and some electrical wires in Tewksbury, according to town police dispatcher Kim Griffin. Power was lost to some homes, and a section of Route 38 was closed because of flooding.
The thunderstorms, Simpson said, brought particularly heavy rains because they were moving through the metro area at about half the speed of typical storms. “Usually, showers move through at around 30 miles per hour, but in this case they were moving at more like 15,” he said.
Marcano, the 18-year-old stranded in the Dorchester underpass, tried to shift his Honda CR-V into reverse and out of the Quincy Street puddle, but “the motor had drunk some water and shut off,” he said.
“I would have waited longer to go out, but the rain hadn’t looked so bad when I left,” he said.
Lifting up the soaked rug under the driver’s seat and peering at the puddle beneath, he added, “It really came out of nowhere.”
globe.com. Nikita Lalwani can be reached at firstname.lastname@example.org. Globe correspondents Jasper Craven and Melissa Hanson contributed to this report.