The results of an experimental study designed to investigate the properties of isolated intense vortices that are formed during rotating turbulent thermal convection are presented. The vortices were generated by uniform heating of the base of a laboratory tank rotating about its vertical axis. Concentrated vortices were found to emerge sporadically, abide for some time and then fade away. Measurements included the spatial frequency of occurrence of vortices and their physical dimensions and characteristic velocities. Theoretical arguments are advanced to explain the observations. Possible geophysical applications of the results are also discussed. ¿ American Geophysical Union 1989