Thunderstorms pose several hazards, whether you are on the ground or in the air, namely lightning, hail, turbulence, icing, downbursts and even tornadoes. Because of these potential hazards, planes don’t fly through thunderstorms. Instead, they fly around them.
Pilots have onboard weather radar and air traffic control support to steer around thunderstorms rather than fly straight through them. In addition to pilots being trained to avoid thunderstorms, modern engineering has led to commercial aircraft designs that can withstand many of these threats.
Lightning for instance, isn’t much of a danger. On average, lightning strikes a plane once or twice a year without incident. Turbulence is a familiar part of flying for pilots and passengers. Turbulence is uncomfortable but not structurally dangerous to the aircraft. Extreme turbulence can cause injuries to passengers, particularly those not buckled in. In addition to being in the vicinity of a thunderstorm, turbulence can be caused by other atmospheric phenomena.
Icing occurs when super cooled water (liquid water that is already below the freezing point temperature), encounters an object that is below freezing. Ice that accumulates on the wings makes it more difficult to maneuver the plane.
Updrafts and downdrafts are vertical air movements that drive a thunderstorm’s circulation. Updrafts in a thunderstorm are rising currents of warm air that can reach several miles high. Downdrafts are sinking currents of cooler air that spread outward as they hit the ground. For aircraft, strong downdrafts are especially hazardous because they can reduce lift and push the plane downward, making it harder to maintain altitude. In severe cases, a downdraft can contribute to a stall if the aircraft cannot generate enough lift to remain safely airborne.
For passengers, the bigger issue associated with thunderstorm weather is usually experienced on the ground — the disruption caused by air traffic delays that are directly related to the weather.
Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on Wisconsin Public Radio at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.
