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.

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.

A flash flood is a rapid rise of water along a stream or in a low-lying urban area, the National Weather Service said. Flash flooding can result from slow-moving thunderstorms, from numerous thunderstorms that develop repeatedly over the same area, or from heavy rains associated with tropical cyclones.

An analysis of National Weather Service job vacancies found that in more than a third of offices overseeing flash flood hotspots, one or more of three senior leadership roles are open.

Recent flash flooding in Texas​, New Mexico​ and North Carolina​ is highlighting the extreme danger of these natural disasters and the need to be prepared.

Along with expected storms and heavy rainfall, Oklahomans could see flash flooding this upcoming weekend. Here's what to know.

Here's what to know about flash floods, emergency systems and how to stay safe as Florida is in the Atlantic hurricane season.

The U.S. President travels to central Texas to survey damage from the July 4 flash flood that killed at least 120 people.