HAMILTON, Mich. -- A line of thunderstorms rolled into West Michigan this afternoon with damaging winds and a Gustnado.
A Gustnado appears to be a small tornado but actually occurs ahead of thunderstorms along a gust front. The Gustnado is surface based, meaning it is not attached to a parent cloud above it. A Gustnado rarely does any significant damage and lasts only a matter of seconds.
This is the official definition of a Gustnado by the National Weather Service:
A slang term for a short-lived, ground-based, shallow, vortex that develops on a gust front associated with either thunderstorms or showers. They may only extend to 30 to 300 feet above the ground with no apparent connection to the convective cloud above. They may be accompanied by rain, but usually are 'wispy', or only visible as a debris cloud or dust whirl at or near the ground. Wind speeds can reach 60 to 80 mph, resulting in significant damage, similar to that of a F0 or F1 tornado. However, gustnadoes are not considered to be a tornado, and some cases, it may be difficult to distinguish a gustnado from a tornado. Gustnadoes are not associated with storm-scale rotation (i.e. mesocyclones) that is involved with true tornadoes; they are more likely to be associated visually with a shelf cloud that is found on the forward side of a thunderstorm.