Photographs and Analysis of an Unusually Large and Long-lived Firewhirl

Abstract

On 30 June 2005, a large and long-lived firewhirl was observed and photographed over a field being burned to remove wheat stubble in central Kansas. With a well-defined boundary focusing vertical vorticity in the immediate vicinity, the meteorological setting appeared to have at least some similarity to those associated with many nonmesocyclone tornadoes. This paper photographically documents the firewhirl and its evolution. In addition, an examination of the synoptic and local meteorological environment settings suggests that a pre-existing frontal boundary contributed to the occurrence and longevity of the firewhirl in this interesting and unusual case. Although they are clearly different phenomena, firewhirls and nonmesocyclone tornadoes appear to share some similarities in formation mechanisms that are illustrated by this case.