Two boys were reported in trouble in Pennypack Creek on Monday afternoon, the Philadelphia Fire Department said. One was rescued and taken to a hospital, but there was no sign of the other.
Police Capt. Joseph Zaffino told WPVI-TV that the boys were jumping off a bridge into the fast-moving water and one never resurfaced.
"If you saw the falls, and the way it's churning after all the heavy rains we had up north, it's almost impossible for our divers," he said. "We had to rescue one of our divers out of that churning water, that's how strong the current is right now."
Inspector Michael Cochrane told WCAU-TV that police divers were continuing the search effort as a recovery operation.
The landslide, in Moon Township, forced a lane closure on University Boulevard, a major thoroughfare, but no one was hurt and no cars were damaged, PennDOT spokesman Steve Cowan said.
Flood watches were in effect Monday evening in the Philadelphia area, northeastern Pennsylvania and much of central Pennsylvania. Heavy rains and thunderstorms were predicted across much of the state Monday and Tuesday.
Flooding in Northampton County outside Allentown left one family stranded in their car until rescue crews pulled them out, WFMZ-TV said.
Officials in northeastern Pennsylvania reported flash flooding throughout Hawley on Sunday.
"It's generally a nasty day," said Walter Drag, of the National Weather Service.
Drag said there had been between 1 and 2 1/2 inches of rain in the region west of the Delaware Valley. He added that the Philadelphia region received a record-breaking amount of rain in June, between 10 1/2 and 14 inches, which has left the ground saturated. That could create a dangerous situation for people in low-lying areas, Drag said.
Flights were arriving up to an hour late Monday evening at Philadelphia International Airport, where the rain earlier had delayed planes by nearly two hours.
PPL Electric Utilities reported about 260 power outages in eastern and central Pennsylvania on Monday evening, down from over 1,000 in the morning. Peco reported nearly 300 customers without power in the southeast, and West Penn Power reported about 670 outages in the southwest.
The Pennsylvania Emergency Management Agency was keeping an eye on the storm.
Last week, heavy rains pelted parts of central and western Pennsylvania, causing severe flooding. Dubois, about 80 miles northeast of Pittsburgh, was among the hardest-hit areas. Residents in that area are still cleaning up from those storms.