A gustnado (gust front tornado) is a small vortex forming along a storm's gust front, where cold outflow air interacts with warm ambient air. Unlike a tornado, it is not connected to a mesocyclone or to the cloud base.
Characteristics
They are generally weak (EF-0, 65–117 km/h), short-lived (seconds to a few minutes), and narrow. They can loft debris and cause localised damage. Often confused with true tornadoes, their formation mechanism differs and they do not appear in Doppler radar detections as mesocyclones.