A microburst is a weather phenomenon that can abruptly generate hurricane force winds that change direction very quickly. A microburst most frequently occurs when a mass of warm and humid air meets cumulonimbus thunderstorms, which greatly increases the ferocity and force of downward deflected winds.
From pioneer work by Dr. Theodore Fujita, of the University of Chicago, microbursts have come to be more understood, and thus, avoided. Fujita identified and defined the occurrence of a microburst by its size, which is 4km in width, or less, and its duration which is up to seven minutes. Hence the term microburst was chosen over severe downdraft, or down burst, although sometimes these terms are often used to describe the gush of cold air bursting down from thunderclouds.
Many plane crashes, especially in the late 1970’s and 80’s, had the powerful wind shear forces of microbursts as the usual suspects for their going down. Since then, a program through LLWSAS (low level wind shear alert system), has helped pilots and airports be forewarned how to best avoid the powerful downdrafts known as microbursts. By using anemometers, or wind sensors, the LLWSAS can detect potential microbursts before they strike.
Pilots, now trained in techniques to both detect, avoid, and cope with microbursts are more alert to the powerful wind shears caused by microbursts. The FAA, Federal Aviation Administration now routinely releases advisories through the ITWS, or integrated terminal weather system. People affected on the ground can learn more just by watching local weather stations or radio.
Some meteorologists are concerned that more warm and humid weather, predicted due to climate change influence, will increase the violence but not the occurrence of microbursts. If this is to be the case, statistics that are now careful collected by LLWAS and the FAA, will be powerful data to be analyzed and reviewed. Most reporting of the evidence to date points to more violent, but less frequent thunderstorms, depending upon whether it is a el Niño, or la Niña warmer ocean mass generating moist air.
In the United States southern, mid west and gulf states, the differences in temperature drive all the dangerous weather systems now studied. Hurricanes, tornadoes, thunderstorms, and floods are all a result of increased moisture and heat, especially in the summer months. It should also be remembered that increase thunderstorms ironically also cause wildfires by lightening strike, so both too much rain, and not enough can be problematic.