Weather cycles bring El Nino events in the Pacific along the coast of Peru. These can occur every few decades but also super large events can occur every few hundred years. These can bring warm water that kills fish and they can bring floods and droughts along the coast and even inland. It appears that these events destroyed many cities in at various times in the past. The Moche (800 CE) and Chimu (1000 CE) civilizations had cities that were destroyed. There was also a large event in 1100 CE that appears to have destroyed cities of the Sican who were known as the goldsmiths of the north coast.

(The Great Courses – Lost Worlds of South America)