Regionale Bezeichnung im Andenraum (aus dem Quechua wayqu, für "Tiefe, Tal") für Schlammlawinen, Muren und Sturzfluten, die nach Starkniederschlägen im Bergland ihren Ausgang nehmen, insbesondere bei El Niño-Ereignissen.
Speziell angelegte Schutzwälder wie der Bosque de protección de San Matías-San Carlos sollen in Peru den Abfluss vermindern und Huaicos vermeiden helfen.
"Apart from earthquakes, the main natural hazard in the city of Trujillo is flooding associated with EN conditions, particularly when rain occurs below 1800 m MSL. These rains give rise to sudden flows and rapidly rising water level in rivers, ditches, and gorges. Under these conditions heavy rock masses and mudflows, locally known as huaycos, are carried by the river, and pose a special risk for certain city districts. The city can be flooded when the capacity of the Moche bed is surpassed and the gorges are activated. Because of the geomorphology of the basin, this response to heavy rains is very fast. As an example, the historical maximum annual discharge in the Moche River (213 068 m3 s−1) occurred in 1998, and the maximum daily peak flow (1000 m3 s−1) on 13 March of the same year was clearly associated with the strong EN event of 1997/98. During the 1998 EN event, the floods damaged the Pan-American Highway, several city sectors, the airport, farming lands south of the city, and even old historical walls in the area."Garcia-Herrera, R. et al. (2008): A Chronology of El Niño Events from Primary Documentary Sources in Northern Peru
- The Influence of El Niño on Settlement Patterns in Lomas de Lachay, Central Coast, Peru (Kalicki et al. 2014)