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.

A flash flood warning is in effect until 9 a.m. for Boston and several communities south of the city, including Brockton, Quincy, and Randolph, officials said Thursday morning. The National Weather Service also issued a flood watch that will remain in effect until 4 p.m. for Rhode Island and eastern portions of Massachusetts and Connecticut.

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.

A flash flood warning is issued when a flash flood is imminent or occurring. If you are in a flood-prone area, move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.

Flash flooding from heavy rain killed at least three people and prompted dozens of rescues in the Ruidoso area of southern New Mexico, officials said — the same area devastated by wildfires last year.

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 .