Even though man has become a powerful creature, able to control mighty forces, nature can still strike terror into his heart when she whips up a storm. What is a storm? Whenever there is something taking place in the weather of a violent nature, it is a storm.
At sea, a storm may be a strong wind or gale. Inland, a storm usually means there is a weather situation that is marked by heavy rain, and often by lightning, thunder, and strong winds.
A storm in the latitudes where the United States lies usually covers an area hundreds of miles across. It represents vast circular whirls of air rotating about a central point of low atmospheric pressure.
Such storms begin where cold dry masses of air moving southward from Arctic regions are met by warm moist air masses moving northward from the tropics. At certain places, great tongues of the warm air thrust their way into the cold.
The tip of such a warm air tongue becomes a spot of low atmospheric pressure, toward which the winds blow, and the storm area develops around it. Where the cold and warm air masses actually meet, they mix only slightly.
The lighter warm air climbs up and over the cold air along a sloping surface. This cools the warm moist air, it becomes saturated, clouds form, and the result may be rain or snow.
In the Northern Hemisphere, the earth’s rotation causes the winds to be deflected toward the right, so the whirl of the storm is counterclockwise. In fact, it’s like a whirlwind on a huge scale.
Typhoons and hurricanes north of the Equator usually originate in late summer or fall over warm tropical waters. They move westward and northwestward in a path that curves to the right.
A tornado is a violent whirlwind. It begins as a black, funnel-shaped cloud that accompanies a larger thunderstorm area. The tip of the funnel may be only a few hundred feet wide but it destroys whatever it touches.
The destruction is caused by the terrific speed of the wind and the terrific reduction in atmospheric pressure. Walls of houses are sucked out and the buildings collapse! Tornadoes are so destructive that in regions where they occur often, people have built special places to hide from their danger.