Operation Whirlwind (Croatian: Operacija Vihor) was a failed Croatian Army (HV) offensive in the Banovina region of Croatia, fought from 11–13 December 1991, during the early stages of the Croatian War of Independence. The offensive employed a single infantry brigade as the main attacking force, supported by a bridging unit and a handful of tanks and armoured personnel carriers. Although the offensive met hardly any resistance in its initial stage, achieving tactical surprise, the operation was poorly planned, supported and executed as a result of limited training and combat experience.