What is wind shear?

Wind shear is a change in wind speed or direction with height in the atmosphere.

Wind shear also refers to a rapid change in the wind over a short horizontal distance experienced by aircraft, conditions that can cause a rapid change in lift, and thus the altitude, of the aircraft.

Some amount of wind shear is always present in the atmosphere, but particularly strong wind shear is important for the formation of tornadoes and hail.

Larger values of wind shear also exist near fronts, and within the jet stream.

Wind shear in an atmospheric layer that is clear, but unstable, can result in clear air turbulence.

Many airports now have wind shear detection equipment near the ends of runways to warn aircraft if it is too dangerous to land.

Wind Shear accidents

Delta Air Lines Flight 191 was an airline service from Fort Lauderdale-Hollywood International Airport, Florida to Los Angeles International Airport, California, by way of Dallas-Fort Worth International Airport. On the afternoon of August 2, 1985, Delta Air Lines Flight 191 crashed while on approach to Dallas-Fort Worth International Airport during a thunderstorm, killing 8 of 11 crew members, 126 of 152 passengers on board, and one person on the ground. Two people later died 30 days or more after the crash, bringing the total fatalities to 137.

More Weather Lessons