gustnado

A gustnado is a type of tornado that forms near the leading edge of a thunderstorm's downdraft, known as a gust front. These vortices draw their spin from wind shear across the gust front. Gustnadoes are typically short-lived, with relatively small diameters, and are often difficult to observe with radar, making them less understood than stronger tornadoes. A gust, in meteorology, is a sudden increase in wind speed above the average, with a temporary peak exceeding 16 knots (about 30 km/h) after accelerating by at least 9–10 knots (about 17–19 km/h). Gusts are briefer than squalls, usually lasting 20 seconds or less, and are often caused by air turbulence around obstacles.12