Question

A flood occurs when water overflows the confines of a stream or other body of water and accumulates over low-lying areas. Floods are classified as flash floods, river floods, and coastal floods. A "flash flood" is a dangerous rise in water level of a stream in a few hours or less caused by heavy rain, ice jams, earthquakes and earthslides, or a dam failure. A flash flood usually occurs within 6 hours of the rain event, typically a thunderstorm. In some cases, the heavy precipitation can produce a wall of water, moving at incredible speeds and with sufficient force to roll boulders, tear out trees, destroy buildings and bridges and scour out new channels. In many cases, flash floods can cause automobiles to be swept away in just 2 feet of moving water. Since the 1970s, flash flooding has caused an average of 200 fatalities per year in the U.S. These flash flood events often differ in rapidity and violence from "river floods" that are seasonal, resulting from spring rains and melting snow. River floods may crest slowly and persist for as much as a week. The record spring 1997 floods on rivers in the Dakotas and Minnesota, notably the Red River of the North, were caused by rapid spring thaw of the heavy snow cover from a record number of blizzard-producing snowstorms. The great Midwest floods of 1993 were essentially a combination of river flooding produced by a persistent weather pattern, but also by the many local flash flood events on the tributaries to the Mississippi and Missouri Rivers. All these local floods contributed a large, but slow, increase in the water volume in the entire river basin. "Coastal floods" are usually associated with tropical weather systems. QUESTIONS: 1. A flash flood crests within [(hours) (days)] of the rain event. 2. The danger in flash floods is due to the [(depth of the water) (power of the moving water)]. Possible answers are in brackets and parentheses. Only pick from the options provided.

Answer 1

1. A flash flood crests within [hours] of the rain event.

2. The danger in flash floods is due to the [power of the moving water].

1. A flash flood typically crests within [a few hours] of the rain event. This means that the water level of the stream rises rapidly in a short period of time after heavy rainfall, usually within a few hours. The sudden rise in water level can be extremely dangerous because it can catch people off guard and leave them with little time to evacuate or take necessary precautions.

2. The danger in flash floods is due to the [power of the moving water]. Flash floods can have incredibly powerful and fast-moving water. The heavy precipitation can create a wall of water that moves at high speeds and with enough force to cause significant damage. This powerful water can roll boulders, tear out trees, destroy buildings and bridges, and even create new channels. The force of the moving water can also sweep away vehicles, even in relatively shallow depths of just 2 feet. The combination of the speed and force of the water makes flash floods extremely dangerous and potentially life-threatening. It is important to stay away from flooded areas during a flash flood to avoid being swept away by the powerful currents.

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