Gustnadoes are short-lived and relatively weak whirlwinds that forms along a gust front.
A gust front is the surge of very gusty winds at the leading edge of a thunderstorm's outflow of air.
Gustnadoes are not tornadoes, since they do not connect with any cloud-base rotation.
However gustnadoes often have a spinning dust cloud at ground level that make them look like tornadoes.
Because of this they are sometimes wrongly reported.
Even though gustnadoes are relatively weak they can still do minor damage.