You would have probably thought you were in a tornado if you ever had been, since microbursts are strong, sudden blasts of winds that can exceed 160 miles per hour.
While the microbursts I have experienced weren’t as destructive as the typical tornado would be, they can still be an alarming event — especially when they spur young trees to suddenly genuflect toward the ground and cause yard furniture to make a tumbling 30-yard dash to the curb.
But just what is a microburst? How do they form? And, how are microbursts different than tornadoes?
How A Microburst Takes Shape
The rise of warm air can create powerful thunderstorms. The updrafts draw in dry air from around the thunderstorm, which cools the storm and slows down the updrafts. As rain falls into dry pockets inside or below the storm, it starts evaporating, and the evaporation process cools the surrounding air.
Evaporation causes the descending air to cool more rapidly, and since cooler air is denser than warm air, it accelerates cold air toward the ground. This is why we often feel a rush of brisk air just before or during a rainstorm, even on hot summer days.
Sometimes, these downdrafts of air can be so intense, they become downbursts. Downbursts are any occurrence of descending air that causes damage. A microburst, on the other hand, refers to downbursts that are concentrated in a small geographic area that measures less than two-and-a-half miles at its longest dimension.
How Much Damage Can A Microburst Cause?
Don’t let the term “micro” fool you. Microbursts can cause macro damage.
Trees, sheds, and windows are common casualties during a microburst. Often, unfortunately, so are planes. In fact, a microburst was known to have caused an Eastern Air Lines Boeing 727 to crash in New York on June 24, 1975 about 2,400 feet short of its Kennedy International Airport runway; of the 124 passengers and crew members on board, 113 died.
A few years later, in 1983, a very powerful microburst struck Andrews Air Force Base only minutes after Air Force One touched down there with President Ronald Reagan aboard.
How A Microburst Is Different From A Tornado
Microbursts and tornadoes can both exert a lot of damage, so it would make sense for some to believe they are quite similar as far as how they form. While it is true that many people often can’t tell whether they had experienced a tornado or a microburst, there are several distinctions between a tornado and a microburst.
First, tornadoes draw air into a thunderstorm, whereas microbursts are the expulsion of air from a storm. While ground observers without weather monitoring equipment available may not be able to decipher whether wind is going into or coming out of a storm, wind directions can be easily determined by a weather vane or Doppler radar.
Second, tornadic winds are curved and can cause erratic forms of damage on the ground, which can be seen in situations where one house may receive extremely severe damage yet the house next door may be virtually spared. Winds in microbursts, however, flow in a straight line. Straight-line wind damage isn’t always evident to layperson observers on the ground, but can be clearly seen from above. Fallen trees are often the most revealing clue to straight-line winds which, when damaged by a microburst and later viewed from the air, will all be laying in the same direction.
Finally, microbursts are far more common than tornadoes. In fact, for every tornado, there are 10 reports of damage from a microburst.