In calm weather, vortexes can survive for well over a minute, during which they descend at between 1 and 2 metres per second. Turbulent, windy conditions, on the other hand, rapidly break up the vortex. There has been little research on the eerie tearing sound emitted by wake vortexes, but it is likely to originate within the rapidly spinning core region, a metre or so in diameter, where the shear in the airflow is greatest. The descent of the vortexes towards an observer on the ground causes the sound to appear loudest some time after the aircraft has passed overhead. In some conditions, the low pressure at the centre of the vortex causes water vapour to condense.
Vortexes also trap water from the engines, which explains the ribbons of vapour.