A case study of convectively-induced clear air turbulence

On 5 August 2005, two commercial 757 airliners encountered severe turbulence over Northwest Indiana, at cruising altitude in the ostensibly clear air after having flown over or around a large convective storm. According to contemporaneous satellite imagery, the planes were roughly 20 km away from any cloud having appreciable optical depth. Turbulence episodes like these are of interest to the aviation community because they occur without warning and cannot be detected by instruments presently on board aircraft.