The Spring Equinox was last Thursday so spring is well underway in East Texas. The day length is increasing and the sun’s radiation is striking the earth more directly, warming its ground. As the land surface warms in the sun, it heats the air over it. Since warm air is less dense, parcels of light weight air begin to rise to cooler altitudes causing water vapor to condense into clouds. Roughly, for every thousand feet of altitude increase the temperature drops 3-5 degrees. So, as the clouds rise they enlarge. Especially when a cold front forces its way under warm moist air, the uplift can be spectacular. Updrafts at the surface of the land sweep huge quantities of energy into the skies and what started as simple white puffs of cloud begin to tower higher, rolling, soaring, billowing and growing darker.
Winds in the thunderstorm clouds rub raindrops against each other generating static electricity. Within the thunderhead, winds race up and down at speeds of up to 250 miles an hour causing massive electrical charges to develop. Pilots are well advised not to fly into these clouds since the winds can rip their wings off. The gigantic sparks we call lightning leap within the clouds and to the ground. Shock waves caused by these blasts of electrical energy create thunder, first rumbling in the distance, then growing in volume to ear splitting cracks as the storm moves closer.
Counting the number of seconds between the flash of lightning and its thunder clap will indicate your distance from the storm. Sound travels at about 1100 feet per second, so a five second delay between the flash and boom means the strike was 5500 feet – a little over a mile away. As the delay between lightning and thunder grow less, it’s time to take cover, unless you have a hankering to test your beliefs in life after death. Lightning can strike more than 50 miles from a storm. The National Weather Service recorded one bolt hear the Dallas/Ft. Worth area that was over a hundred miles long. According to the National Weather Service, about 95 people die from lightning strikes each year in the United States and hundreds of others receive permanent crippling injuries. Although a lightning bolt only lasts about 1/10th of a second, the energy released is tremendous. The average lightning bolt carries 150 million volts of electricity at approximately 125,000 amperes! Scary!
The maturing cloud tops tower to 50,000 feet or higher with rain streamers reaching out ahead. Sometimes the sky takes on a yellowish or yellowish-green color. Bursts of downward rushing cold wind whips trees, the sky blackens and hail as large as eggs may lash the ground. In the worst-case scenario, sinuous, rolling horizontal masses of air at ground level twist upward and begin to rotate creating a tornado, with winds as high as 318 miles per hour, roaring and bellowing across the land like a maddened freight train. Trees are ripped from the ground, roofs sail through the air, buildings disintegrate, cars are snatched up and thrown like toys, entire communities disappear and people die.
The months of April, May and June are peak periods during which nature exhibits its most violent power while humans and their works often receive severe lessons in humility and perspective. In the face of rampant natural forces, human enterprises take on a distinctly diminished stability and permanence. What is here now and seemingly always has existed, can be gone or reduced to rubble in moments.
Severe storms are a fact of life in this part of the country, so get ready to enjoy the ones that are no threat, avoid those you can and survive any you cannot escape. Generally, spring and early summer are pleasant and beautiful times here and in the absence of damage and death, even severe storms have great beauty and aesthetic magnetism. Enjoy the sights and fragrances of spring flowers and the sounds of spring bird songs, but be prepared for the dangers of nature’s greatest spectacles!
Dr. Risk is a professor emeritus in the College of Forestry and Agriculture at Stephen F. Austin State University in Nacogdoches, Texas. Content © Paul H. Risk, Ph.D. All rights reserved, except where otherwise noted. Click firstname.lastname@example.org to send questions, comments, or request permission for use.