The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Sunday, May 16, 2004

Thunderstorms are Marvelous Examples
of Nature's Power
Ro Wauer, May 16, 2004, The Victoria Advocate, © 2004

Because of the abundant examples of storms we have experienced in recent weeks, I am repeating a nature note on thunderstorms that appeared in the Advocate on September 13, 1998. It is worth repeating:

Building storm clouds display Mother Nature's immense power and can be counted among one of the most awe-inspiring sights on earth. Thunderstorms represent violent movements of air. They occur as a result of strong uplifting drafts that sometimes build the clouds to heights in excess of 75,000 feet.

Meteorologists tell us that thunderstorms develop in three stages. First, small cumulus clouds build into larger masses of billowy, mushroom-shaped clouds called cumulonimbus, the familiar thunderheads that can be seen for more than 100 miles. Second, when the ascending air reaches a low enough temperature, precipitation occurs. Tiny water droplets are blown wildly around within the clouds until they join together to form larger droplets that are too heavy to remain in cloud form. Then gravity takes over, and the droplets begin to fall as rain, ice crystals, or snow. Huge downdrafts are created when this occurs as the falling precipitation cools the air below, producing the third stage. The entire cloud then becomes a sinking mass of air and precipitation.

Lightning is an electrical charge within a thundercloud or between it and the earth. Charges between clouds or between clouds and the earth are released when electrical pressure becomes high enough. The first strokes are within a cloud; approximately 65 percent of all discharges occur there or between clouds.

Lightning to the ground starts with a relatively thin "leader" stroke from the cloud and is followed immediately by a heavy return stroke from the ground. A single lightning strike goes back and forth from cloud to ground many times in less than a tenth of a second. A lightning discharge is incredibly powerful - up to 30 million volts at 100,000 amperes - but is very short in duration; hence, the power of lightning has never been harnessed.
The total energy of a major thunderstorm far exceeds that on an atomic bomb. The sudden heat from lightning causes compression of shock waves that we call thunder. The distance of these can be estimated by sight and sound. Light travels at about 186,000 miles per second, and sound travels only 1,100 feet per second, or one mile in a little less than five seconds. You, therefore, can judge the distance of a storm by timing how long it takes for thunder to reach you after you see the lightning flash. If you hear the thunder 40 seconds after the lightning, then you are eight miles from the storm.

The energy of one of our coastal thunderstorms is almost beyond imagination. I can think of few other experiences that demonstrate so vividly the power of Mother Nature.

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