LIMA, Peru (AP) — Peruvian authorities said Monday they located the bodies of a father and son killed when intense rains in the country’s south triggered mudslides affecting some 5,500 homes, forcing many people to evacuate.

Father and son were swept away by a landslide in the city of Arequipa in a neighborhood built directly over an ancient natural watercourse. According to experts, these homes encroach on a path that has carried torrents of water for centuries during periods of heavy rains.

Authorities in Arequipa have called on the country’s interim president to declare a state of emergency in the region. Meanwhile, regional Gov. Dr. Rohel Sánchez Sánchez announced that multiple refuges were being opened across the Arequipa region. He also announced that food and tents were distributed by the National Institute of Civil Defense and the regional government of Arequipa.

The El Niño Costero climate phenomenon has been the cause of the recent weeks of heavy rain, forecasters say.

According to authorities, Pacific waters are warming and El Niño Costero is expected to strengthen slightly in March. The warming of ocean waters leads to high evaporation rates and extreme rainfall, as well as increased river flows.