A new software tool has been developed to simulate surface wind speed and direction at the 100m to 300 m scale. This tool is useful when trying to estimate fire behavior in mountainous terrain. It is based on widely used computational fluid dynamics technology and has been tested against measured wind flows. In recent years it has been used to support fire management decisions to improve firefighter and public safety, understand the environmental conditions associated with entrapment fires, improve prescribed fire prescriptions, and estimate fire potential. Outputs from this tool include tiff images, GIS shape files, and FARSITE wind input files.