The Historic South Carolina Rainfall and Major Floods of October 1-5, 2015

Abstract

A record setting and historic rainfall event occurred October 1-5, 2015, producing widespread and significant flooding across much of South Carolina. The rainfall resulted from several atmospheric and hydrometeorological factors. The record rainfall triggered flash floods and riverine flooding that resulted in emergency evacuations, travel disruptions, personal property damage, business losses, bridge collapses, dam failures and tragic loss of life. Precipitation records were broken from the midlands to the coast, with totals ranging from 10 to over 26 inches of rain. Sixteen National Weather Service Cooperative Weather Stations set new 24-hour rainfall records for October. The amount of rainfall during the event at various locations and for various durations (6-, 24-, 48-, 72-, 96- hours) had a statistical probability of occurrence of 0.1% or 1 in 1,000 chance of happening in any given year, according to the National Oceanic and Atmospheric Administration (NOAA) Atlas 14. Streams and creeks swelled out of their banks with at least 17 U.S. Geological Survey (USGS) stream gages reaching record peaks. The event was the worst flooding most residents had ever experienced. This report will provide a synoptic and chronological overview of how the historic rain and flooding unfolded with documentation of the meteorological and hydrological records. A comprehensive interactive journal of the event is available on-line at http://www.dnr.sc.gov/flood2015.