A Brooklyn roadway was transformed into a lake when a thunderstorm hammered the Big Apple with torrential downpours Monday evening.

Carroll Street took the brunt of the flooding, with a whole section of the street blocked off with orange barricades that were halfway covered in water themselves, video posted by the NYC Scanner account shows.

Debris could be seen floating in the water, and the base of the street sign at the corner was about halfway covered, the video shows.

The exact intersection where the clip was taken was unclear, but a tweet posted by the city’s office of emergency management Monday evening warned New Yorkers of “extensive traffic delays” in the area of Carroll Street and Fourth Avenue.

Twitter user Julie Chang shared a video taken by friend Adrienne Zhao of cars parked at that intersection, with water completely covering their wheels.

Elsewhere in Brooklyn, another video posted Monday night shows a fearless pedestrian crossing a street soaked in knee-high water in Williamsburg.

City Council Speaker Corey Johnson reported a number of areas in the city hit by flooding — including the Long Island Expressway near Francis Lewis Boulevard, where a good Samaritan was shown on video getting out of her car, grabbing an orange construction cone and clearing debris that was clogging a sewer grate under an overpass.

The thunderstorm moved in soon after 6 p.m., soaking the city after two days of upper-90-degree heat this weekend and temps in the high 80s on Monday.