At times rain pours down so fast that it is as if an enormous bag full of water had burst open and spilled all its water at once. A rain of this kind is called a cloudburst.
A cloud cannot really burst. A rain cloud has nothing on the outside to shut in its billions of droplets of water. But, even when the droplets become big drops, strong upward currents of air may keep them from falling. At last, however, the drops are too big and heavy to be held up. They fall with a rush, and we have a cloudburst.
In a cloudburst enough rain to make a layer several inches deep on the ground may fall in a very short time. In Holt, Mo., for instance, 12 inches of rain fell in one hour on June 22, 1947. This is more rain than many parts of the world get in a year. And in Jefferson, Iowa, two-thirds of an inch fell in just one minute on July 10, 1955!
