The Sechura Desert is a coastal desert located south of the Piura Region of Peru along the Pacific coast and inland to the foothills of the Andes Mountains. Its extreme aridity is caused by the upwelling of cold coastal waters and subtropical atmospheric subsidence, but it is also subject to occasional flooding during El Niño years. In 1728, the town of Sechura was destroyed by a tsunami and was later rebuilt in its present location. In 1998, runoff from flooding rivers caused the formation of a temporary lake some 145 km (90 mi) long filling the Bayóvar Depression. Short rivers flowing across the desert from the Andes support intensive irrigation-based agriculture.