» LIVE UPDATES: Latest on flooding, clean-up efforts in aftermath of Ida in the Philadelphia region

Ida’s moisture-laden remnants evidently spawned multiple tornadoes throughout the region in an hours-long siege Wednesday, ripping off roofs, uprooting trees, and snapping utility poles. And the storm that also set off road-closing downpours isn’t quite done with us.

Forecasters are warning that the Philadelphia region could experience its most robust river flooding in a decade during the next two days. Late Wednesday night, floodwaters swamped Columbus Boulevard as the Delaware River rose nearly 1.5 feet above flood stage.

“We’ll probably have a lot of it,” said Sarah Johnson, a lead meteorologist at the National Weather Service Office in Mount Holly. The Delaware River was forecast to crest late Friday close to the moderate flood level at Trenton.

» READ MORE: Devastated communities in Bucks, Burlington Counties assess damage after ’100-year flood’

“Major” flooding levels were measured late Wednesday night along the Schuylkill at Norristown and in Philadelphia. At 30th Street, the Schuylkill was forecast to rise more than 10 feet above flood stage Thursday morning at the government’s newly installed monitoring gauge.

In New Jersey, Gov. Phil Murphy declared a state of emergency.

As night progressed, school cancellations grew. Norristown Superintendent Christopher Dormer said that schools would be closed Thursday. Even virtual classes were canceled. Cheltenham canceled classes, and schools also will be closed in the Central Bucks School District. Also in Bucks County, the Centennial School District canceled in-person instruction Thursday but said students would be expected to log on for virtual schooling.

No evacuations were planned, but along the Schuylkill in West Norriton Township, historicaly one of the more flood-prone communities in the nation, officials had set up a shelter at Norristown Area High School, said Jason Bobst, the township’s emergency director.

Philadelphia also was set to open shelters in West Philadelphia and Roxborough “out of an abundance of caution,” said Fire Commissioner Adam Thiel.

“This is expected to be a pretty severe flooding event,” said Thiel.

Save for that river flooding, Thursday and Friday actually should be quite pleasant early September days with sunshine and temperatures in the 70s, a remarkable and welcome contrast to an afternoon and night of chaos and jumpy, indefatigable cellphone alarms. About 40,000 Peco customers lost power.

Stream and road flooding was widespread, and for a solid three hours starting about 4:15 p.m., the region became Tornado Alley east. The weather service issued 14 tornado warnings for the region from deep southwestern Chester County to Mullica Hill, Gloucester County. Tornadoes already are well above normal this year in Pennsylvania and New Jersey.

The weather service said it had radar-confirmed two of the tornadoes, and the one that struck Mullica Hill almost certainly will be verified when weather service teams inspect the damages.

Ellen Capriotti, 50, a teacher at Clearview Regional High School who lives on Forest Woods Drive in a development called The Enclave at Forest Woods, said she and her husband, Dave, and two of their children were waiting for a pizza delivery when they heard the approaching winds.

“It became, ‘Grab the dog and go down into the basement,’ ” she said. “Things were hitting the house. I was talking to my daughter and she was answering me, but I couldn’t hear what she was saying. ... A neighbor had a tree go through their front door. Thank God my family and I are OK.”

One of the radar-confirmed tornadoes was a “large and extremely dangerous tornado” near Willow Grove, Montgomery County, late in the afternoon. The roofs were blown off several buildings along Norristown Road in Horsham Township, the weather service reported.

About two hours later, shortly after 7, it confirmed a “large and destructive” one in southeastern Bucks County, and a trained spotter in Tullytown said it skipped across the river to adjacent South Jersey.

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Reports of tornado-like damage came from other places, including the area around Cherry Hill, where multiple trees and wires were ripped down, and that, too, might have been a tornado, the weather service said.

In short, on an afternoon and evening of atmospheric bedlam, the weather service was inundated with storm reports.

Besides the suspected twisters, late-day downpours put an unwanted Venetian touch on some local roads.

“We have a lot of roads closed in Bucks and Chester,” said Brad Rudolph, a PennDot spokesperson. Among them were portions of Route 1 in Bucks County and the heavily used Route 30 Bypass near Route 113 in Chester County.

Numerous other road closings were reported throughout the region.

The rain potential was well forecast, the “T” word was mentioned as a possibility, particularly for areas south and east of Philadelphia. However on Wednesday, the danger zone expanded well to the north and west, all the way to the Lehigh Valley.

The core of Ida’s leftovers passed west of the region, and in the case of tropical storms and their remnants, areas to the east of the center become most vulnerable for tornadoes, said the weather service’s Johnson.

“There’s so much spin involved,” said Dave Dombek, senior meteorologist with AccuWeather Inc. While land surfaces and trees cause friction that reduces a storm’s wind speeds, he said, “It’s still churning at mid and upper latitudes.”

In this case, Ida’s moisture was getting a lift from upper-air winds and a stalled front that were conspiring to wring out moisture.

Given the forecasts, all morning New Jersey and Pennsylvania officials had urged people to stay home.

“Imagine a month, two months of rain in 24 hours,” Jeff Jumper, meteorologist with the Pennsylvania Emergency Management Agency, said at a news briefing.

Coatesville, Chester County, reported better than 8 inches of rain.

Upstream rains also were a concern for the main stem rivers.

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Sometime Friday the Delaware River at Trenton is predicted to crest near the “moderate” flooding level at 22.6 feet, which would be the highest level since the river was swollen by Hurricane Irene’s remnants in August 2011. Flood stage is 20 feet.

The Delaware experienced significant flooding in 2004, 2005, and 2006, but in the last 10 years for whatever reasons it has been remarkably well-behaved despite any number of downpours.

Ice jams sent the waters just above flood stage in January 2014, but it hasn’t reached the 20-foot level since.

Late Wednesday night, major flooding levels were reported at multiple locations, including Neshaminy Creek near Langhorne, Perkiomen Creek at Graterford, East Branch Brandywine Creek near Downingtown, and Brandywine Creek at Chadds Ford. Moderate flooding was reported in multiple other locations along the Delaware River, up through Easton.

No more rain will be added to the waterways around here at least until late next week. And no tornadoes; some might say, like the good old days.

Said Thiel, the fire commissioner, “There used to be a time when we thought tornadoes didn’t happen in Philadelphia.”

Staff writers Melanie Burney, Kristen A. Graham, Maddie Hanna, Frank Kummer, Andy Maykuth, Kevin Riordan, and Ellie Rushing contributed to this article.