Microbursts

One of the least known weather phenomena is the microburst. It is a wind occurring beneath certain clouds that is strong enough to damage buildings, knock down trees, and crash airliners. Microbursts can produce wind speeds higher than 175 miles per hour, which is greater than many tornadoes and hurricanes.

Microbursts are fast-moving columns of air that develop beneath cumulonimbus clouds. These are the same clouds that produce thunderstorms and tornadoes. The air develops quickly and moves straight down from the cloud base. It then moves along the ground and curls back up and around in a circular manner. They are also called “cloud sneezes.”

Since 1975, eight airline crashes have been directly attributed to microbursts. The crashes occur during either takeoff or landing. Let’s consider an aircraft landing as an example. Flying low in its approach, the aircraft encounters the outer area of the microburst’s curling wind. The pilot senses the updraft and forces the nose of the airplane down to compensate. As the airplane continues, it encounters the strong downdraft at the center. Because the nose of the plane is already lowered, the down-moving air forces the nose rapidly lower, and the pilot is unable to compensate. This forces the airplane down to the ground.

The most famous microburst airline crash was Delta Airlines Flight 191 at Dallas/Fort Worth International Airport on August 2, 1985. The airliner crashed on approach due to a microburst, and 137 passengers and crew members died.

As a result of that airliner crash, the government sought ways to detect microbursts with various types of weather radar. This and other precautionary measures have lessened the number of airline crashes due to microbursts.