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.

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.

More than 111 people have died across six counties after flash flooding from heavy rain began affecting the state last week.

As crews search for missing people after flash floods killed at least 120 in Texas, cities across the U.S. grapple with rising flood waters.

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.

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.

Flash flooding has been in the spotlight in the last week, with several record breaking flood events occurring nearly back-to-back across the country. CNN’s Tyler Ory explains why they’re becoming more intense .

Here's what to know about the deadly flooding, the colossal weather system that drove it and ongoing efforts to identify victims.