The tropical storm left at least six dead as it moved up the East Coast on Tuesday, downing trees and causing millions to lose power. The storm also triggered "widespread" rainfall amounts between 3 to 6 inches, including isolated amounts of up to 10 inches across the Interstate 95 corridor, according to Fox News Senior Meteorologist Janice Dean
"The storm is well out of the way but we are seeing incredible amounts of damage, including flooding reports," Dean said Wednesday on "Fox & Friends."
The worst flooding was reported in the Philadelphia area.
The Schuylkill River in the city was projected to crest early Wednesday at 15.4 feet, its highest level in more than 150 years.
The river only got to around 13.5 feet in Philadelphia early Wednesday but left significant flooding behind.
“The worst of this event is yet to come,” Adam Thiel, Philadelphia’s fire commissioner and director of its Office of Emergency Management, said Tuesday afternoon.
The river topped its banks in low-lying Manayunk, turning bar-lined Main Street into a coffee-colored canal.
A major expressway bridge in Philadelphia was closed in both directions Wednesday morning due to a construction barge that ended up wedged under a bridge.
The barge, used in conjunction with a nearby bridge construction project, became loose on the water during Tuesday’s storm, officials with PennDOT told FOX29.
Workers were spotted out Wednesday trying to secure the barge, but officials said it was still too dangerous to move it as the river continues to rise.
The Schuylkill was forecast to reach “major” flood stage early Wednesday near Norristown, the Philadelphia Inquirer reported.
In eastern Pennsylvania, a 44-year-old Allentown woman was among the six killed in the storm after encountering high waters on a street in Upper Saucon Township that swept her vehicle downstream Tuesday afternoon, the Lehigh County coroner’s office said.
In Doylestown, officials said four children were treated for minor injuries after high winds partially tore the roof off a daycare center, FOX29 reported.
Also in the Philadelphia suburbs, rescue workers in Delaware County were searching for a young person who fell or jumped into the fast-moving water of a swollen creek, said Timothy Boyce, the county emergency services director.
Tornadoes were confirmed by the National Weather Service in Virginia, Maryland, Delaware and New Jersey.
As of Wednesday morning, power-outage tracking website poweroutage.us said over 2.4 million customers remain without power, with the greatest number in New Jersey, Connecticut and New York.
Dean said that Isaias was "one of the most damaging storms" the Northeast has ever experienced.
"Over 3 million people without power because of this tropical storm, another indication it doesn't take a major hurricane to cause incredible damage," Dean added.
The storm is now well into Canada becoming post-tropical on Tuesday night. Breezy conditions will continue across the Northeast and New England on Wednesday in the storm’s wake.
Fox News' Janice Dean and the Associated Press contributed to this report.