Maryland is subject to flooding from several different sources. Flash floods tend to come after short periods of heavy rain and most often affect small streams and creeks. General flooding comes from more prolonged steady rain and tends to affect larger streams and rivers. Major rivers such as the Potomac and Susquehanna often reach flood stages because of events in distant areas of their watershed. Finally, hurricanes and tropical storms can cause surges that create tidal flooding along Maryland’s bays and their tributaries.