INSIDER PHOTOS: We waded into parts of Philadelphia that are underwater after remnants of Hurricane Ida swept through the region

Firefighters deployed a motorboat in Center City

Long-time residents said they have never seen such flooding

Floodwaters were expected to rise throughout the day

The Vine Street Expressway is normally jammed with traffic

The highway is a major artery that cuts through the center of Philadelphia

The floodwater was at least 10 feet high

It's unclear how many cars are under the water

Flooding was worse closer to the Schuylkill River.

The flash flooding was accompanied by several tornadoes in the area

It's not yet clear when the highway will reopen

The Vine Street Expressway connects to several major highways

Parts of the expressway looked like a river itself

Floodwaters destroyed cars at several apartment buildings

In some cases, the water rushed in before owners could act

Firefighters were working to clear streets in Center City

Flooding was particularly bad near Arch Street and 22nd

Flooding blocked access to buildings in Center City

Dozens of cars around the city were at least partially submerged

Firefighters worked all morning to clear the streets

First-responders deployed a special operations unit

Floodwaters were several feet high in parts of Center City

The water forced Center City to establish detours that stretched along several blocks in the area

Some residents tried to access their flooded vehicles

The floodwaters appeared to cause some property damage

Several contiguous blocks were underwater west of City Hall