Alluvial Fan 1 : Natural Disaster. A fan- shaped deposit of sediment that accumulates where a high- gradient stream flows out of a mountain front into an area of lesser gradient such as a valley
National Park Service, U.S. Department of the Interior, Geologic Resources Division, Natural Resource Program Center, Wolf Trap National Park for the Performing Arts, Geologic Resource Evaluation Report, Natural Resource Report NPS/NRPC/GRD/NRR 2008/041, Technical Geologic Terms, Denver, Colorado, USA 2008. http://www.nature.nps.gov/geology/inventory/public ations/reports/wotr_gre_rpt_view.pdf, (ND/ Lndsld - Amer) {923}