Severe wildfires have increased in number and size throughout the Southwest in recent years. These fires pose a serious threat to human life and property and to ecosystems not adapted to them. Years of fire exclusion, heavy fuel loads, urban encroachment of wildlands, and broad-scale climatic patterns have exacerbated the problem and present serious challenges to land managers in fire-prone environments. The ability to quantify risks and hazards associated with large fires and their potential impact on resources at various spatiotemporal scales is necessary to effectively meet these challenges. In this paper we describe ongoing research aimed at developing an integrated GIS model for assessing fire hazard in the Southwest. The model is designed to link human dimensions and natural sciences through the integration of four interrelated components: a) simulated climate factors such as precipitation, temperature, and ENSO cycles, b) biological factors such as vegetation and fuels, c) fire ignition, size and behavior characteristics, and d) human dimensions such as land use patterns, institutional factors, and behavioral patterns. We plan to develop apply the model in four mountain ranges in the Southwest. The model will provide the first fully integrated, spatially explicit assessment of climate, human dimensions, and biophysical parameters for assessing fire risk at the regional level in the Southwest. The various components and applications of the model will be discussed and preliminary findings from initial field research will be reviewed.