ON-006-22M Alluvial Fan Mapping of Gilpin County, Colorado (Map) Details The Colorado Geological Survey develops and provides a variety of geologic hazard maps for various state and local governments with land use and hazard mitigation planning in mind. To prepare for post-wildfire natural hazards, the CGS has mapped alluvial fans as well as high-angle fans and (or) debris fans. Areas with these landforms are at risk for debris flows and (or) mudflows, especially after wildfire events. Using available Colorado LiDAR datasets, both known and previously unrecognized alluvial fans were compiled, mapped, and defined. This map is part of a statewide effort to develop county-specific maps of alluvial fans in Colorado. To the map: ON-006-22M Alluvial Fan Mapping of Gilpin County, Colorado (Map) Download the data as an ArcGIS Pro project package (.ppkx) here: ON-006-22D Alluvial Fan Mapping of Gilpin County, Colorado (Data) – v20251120 Citations Lindsey, K.O., Perman, E.A., Zhou, Wendy, Fitzgerald, F.S., and Lovekin, J.R., 2025, Alluvial fan mapping of Gilpin County, Colorado (map): Colorado Geological Survey Online Series 006-22M. https://coloradogeologicalsurvey.org/publications/alluvial-fan-map-gilpin-colorado/