To the south and east, they aren't wondering. By 1:45 p.m. Wednesday, it was clear that this was no ordinary rainstorm.
That was when the first call came in to the Marcus Hook-Trainer Fire Department that a driver was stuck in his car under a bridge at Main and Pennsylvania Streets in Trainer, firefighter Josh Atkins said. When he and colleague Tim Stabelli arrived, Atkins said, the elderly man behind the wheel was "up to his chest in water. He was scared and waving to us."
The firefighters donned life vests and safety lines and walked into the water - which soon reached chest-high - to rescue him. It was one of six rescues they executed, including one of a mother and two young children.
Their boss, Chief James McClure, a 22-year veteran, said he had never seen the likes of the raging waters. Still, Atkins said, larger trucks were trying to make it through the floodwaters. "I was stopping them," he said.
In Trainer, a car got stuck in water after the driver evidently ignored a police car stationed to prevent just such an occurrence.
"The [unflattering characterization deleted] drove right past me," Police Sgt. Rick Cominskie said. The water reached all the way to the truck's rearview mirrors.
A dump truck became stuck in water in Prospect Park.
Water up to four feet deep was reported in parts of Delaware County, the National Weather Service said.
A busy portion of Route 291 - the erstwhile Industrial Highway - at Stewart Avenue in Ridley was reduced to one lane, and the Broad Street ramps of I-95 in Philadelphia were closed briefly, said Gene Blaum, a spokesman for the Pennsylvania Department of Transportation.
Flooding was widespread in Camden, police said, and parts of Route 130 were flooded in Collingswood, Haddon Township, Mount Ephraim, and Gloucester City.
The latest round of trauma was the result of a powerful slug of rain that moved with all the vigor of a cork in a pond on a windless day.
The rain was affiliated with a weak area of low pressure over the Delaware Bay, according to Alan Cope, the science and operations officer at the weather service's Mount Holly office.
The official rainfall total for the day at the airport, 2.88 inches, was just 0.01 shy of the record for the date. That was set in another hot summer, 1994.
In the last five days, 5.1 inches has fallen in Philadelphia, more than had fallen in from April 27 through Friday.
Coincidentally, Friday was the day that the Pennsylvania Department of Environmental Protection announced that it was concerned about a lack of rain. It said an interagency meeting would be held next week to decide what to do next.
That may be a short meeting.
Contact staff writer Anthony R. Wood at 610-313-8210 or firstname.lastname@example.org.
Inquirer staff writer Darran Simon contributed to this article.