The Andean climate is influenced by El Niño-Southern Oscillation (ENSO) events, which are associated with a band of warm water, which develops in the equatorial Pacific. El Niño events generally produce intense rainfall at the low altitudes along the Pacific side of the Andes, while areas above 2,000 m receive less rain and experience higher temperatures than normal (Garreaud, 2009). The strongest El Niño rainfall anomalies occur during the austral summer (December–January–February) and are associated with heavy rainfall and flooding along the coast of northern Peru and southern Ecuador (Sulca et al., 2017). During La Niña years (when the sea surface temperature across the equatorial Pacific is lower than normal) the opposite generally occurs (Garreaud, 2009). In the central and southern Andes ENSO has a less marked influence, but El Niño has been associated, for example, with increased rainfall in Central Chile (Verbist et al., 2010; Robertson et al., 2013) and increased streamflow in Patagonia (Rivera et al., 2018). In the Tropical Andes, though, variations of glacier mass balance are subject to ENSO (Veettil et al., 2017).
From collection: The Andean Glacier and Water Atlas