A High Resolution Lightning Map of the State of Colorado

For the state of Colorado, 10 years (2003–12) of 01 April–31 October cloud-to-ground (CG) lightning stroke data are mapped at 500-m spatial resolution over a 10-m spatial resolution U.S. Geological Survey (USGS) digital elevation model (DEM). This cartographic mapping of lightning data benefits weather forecasters, wildland fire managers, those who maintain lightning-vulnerable infrastructures, and contributes to a deeper understanding of atmospheric processes as they occur over Colorado's topographically diverse landscape. The data exposes orographic and rainshadow effects, mesoscale meteorological effects, and the influence of low and mid-level moisture sources. Geospatial analyses that quantify lightning activity by elevation, physiographic region, and mountain range identify lightning/landscape relationships, while temporal explorations identify thunderstorm initiation zones, characterize storm movements, and outline the temporal fluxes of moisture entering the state. Major findings include 1) a shift from early-to-late warm season lightning density from east-to-west across the state, 2) the relationship between lightning days and lightning density in mountain ranges, 3) high contrasts in lightning activity across the San Juan Mountains, 4) an outward-radiating pattern of storms in the San Juan Mountains, 5) more than two-thirds of Colorado's population lives in the nine most struck urban clusters and 6) a sharp increase in stroke density observed above 3200m(10 500 ft).