Tornados cause more than one third of the total insured loss due to all natural hazards in the United States. The current design of civil engineering structures for wind loads is based upon model tests in low-speed boundary-layer wind tunnels that generate straight-line winds. Winds resulting from tornados are far from being simple boundary-layer types. Tornados are vortices with significant tangential and vertical velocity components as well as large pressure gradients. Assessment of accurate wind loads in tornados is the first step toward better design of structures that will save lives and reduce property loss. Several model tornado simulators have been tested to assist in determining the mechanism of simulation and important flow parameters that are required to assist in designing a prototype simulator that will be housed in the Wind Simulation and Testing Laboratory at Iowa State University (ISU). This paper focuses on the design process that led to the latest model simulator whose design will be used to build the prototype tornado simulator.