TY - RPRT TI - Geographic information system (GIS) procedure for preliminary delineation of debris-flow hazard areas from a digital terrain model, Madison County, Virginia AU - R. H. Campbell AU - P. G. Chirico PY - 1999 DO - 10.3133/ofr99336 UR - https://pubs.usgs.gov/publication/ofr99336 ID - ofr99336 ER -