Straighter, smoother streams flow more violently than those that meander due to a reduction in friction. Areas with steeper terrain can see water accelerate downhill at a much faster rate causing a more destructive flash flood than flatter, open areas.

At 3:47 p.m. on Thursday, the NWS Newport/Morehead City NC released a flash flood warning in effect until 7 p.m. for Dare County.

Radar shows the rain is coming down at a rate of a half-inch to 1.5 inches per hour, according to the National Weather Service.

With rain coming down so fast, storm drains couldn't handle the deluge of water. On Interstate 93 in Quincy, all were lanes closed at one point because of extreme flooding during rush hour. At least five cars were stuck on the highway until the water receded.

The mountain village of Ruidoso has returned to the grim rituals of rebuilding from flash flooding. Crews are working to clear twisted metal, broken trees and muddy debris from streets and homes days after monsoon rains triggered a deadly flash flood in southern New Mexico.

The warning is in effect until 9 a.m. for Boston and several communities south of the city, according to the National Weather Service.

At least three people were killed by historic flash floods in a New Mexico mountain community that suffered devastating wildfires last year, officials said late Tuesday.

Back-to-back flooding disasters in recent years — in Texas, New Mexico and Kentucky, among many others — have showed that preparing for flash flooding is a new necessity as the planet warms.