Flash floods triggered by torrential rainfall disrupted road and MBTA traffic Saturday and stranded several motorists, forcing rescues by police and firefighters.
The National Weather Service issued a flood advisory for Boston Saturday afternoon in anticipation of thunderstorms and scattered showers that were expected to continue through the weekend. The weather service also issued flood advisories for several counties including Bristol, Middlesex, Worcester, Essex, Norfolk and Plymouth.
Heavy rains, which began about 2:30 p.m. and turned lighter by evening, totaled 2.1 inches in Boston and 3.3 inches in Cambridge, said Nicole Belk, a meteorologist with the National Weather Service in Taunton.
With little rain for more than two weeks, dry soil was unable to soak up the water and threatened to cause run-off, exacerbating flood concerns for communities outside Boston, said Kim Buttrick, another meteorologist with the National Weather Service.
"It's like being in a city where everything runs off cement," Buttrick said.
Drivers throughout Greater Boston fought through flooding caused by the rapid downpours.
State Police and the Somerville Fire Department rescued a woman stranded on top of her car by a flash flood in Somerville about 3:45 p.m.
"She’s not a swimmer," Sergeant Matthew Murray, a State Police spokesman, said of the stranded woman, who climbed atop her car in the flooded Assembly Square underpass.
A total of five motor vehicles with an unknown number of occupants became trapped in rising floodwaters at the same underpass and required assistance, a traffic advisory from the State Police said. The underpass remained closed Saturday night.
Flooding also occurred on Storrow Drive, causing closures in both directions at the Massachusetts Avenue and the Longfellow bridges. The road had one passable lane in each direction as of 10 p.m.
While heavy rains disrupted traffic, they also were an obstacle for MBTA passengers and officials.
"We actually did have flooding" that closed the Downtown Crossing T station at 3 p.m., said Lydia Rivera, spokeswoman for the MBTA. Service resumed when water receded about a half-hour later, she added.
Train traffic was diverted on the commuter rail and the Red, Orange, and Green lines due to weather related problems, according to MBTA alerts.
Inbound service for the Fitchburg/South Acton commuter rail line was terminated at the Porter Square station due to weather concerns, according to an MBTA alert.
Forced to bypass Wollaston station, the Red Line used shuttle buses between the North Quincy and Wollaston stops.
Similarly, the MBTA said, the Orange Line ran shuttle buses between Roxbury Crossing and Ruggles, while the Green Line, in an alert, warned passengers of delays up to 20 minutes because of the weather.
One positive aspect to the storms, Buttrick said, was the cooling down of a recent stretch of temperatures above 90 degrees. However, she said, the relief will not last.
The National Weather Service predicted scattered showers Sunday. Monday, a sunny day with a high of 86 degrees is expected.
On the beat
Columnist Shirley Leung says Boston mayor-elect Martin J. Walsh should focus on middle-class housing. Read more