Thunderstorm dangers include fierce up and down winds, called updrafts and downdrafts. These cause extreme turbulence that makes an airplane hard to control. Near the ground, thunderstorms sometimes create quick changes in wind speed and direction, called wind shear, which has caused several crashes. Hail stones can heavily damage airplanes, including breaking windshields, and turbine blades in jet engines. Thunderstorm rain can sometimes be heavy enough to drown engines, including jet engines.
Lightning can temporarily blind pilots.