More rain is forecast but experts say unusual coastal water anomaly that fuels it is subsiding

Ecuador’s National Institute of Meteorology and Hydrology (INAMHI) isn’t having much luck explaining the weather. “This is not an El Niño,” says José Olmedo, director of INAMHI. “The reason for the exceptional rainfall is a rare phenomenon of very high ocean temperatures near the coastline of Ecuador and Peru. The news media continues to call it an El Niño, which is something very different.”

Landslide on the Pan Americana norte near Cuenca. (El Mercurio)

Whatever it’s called, INAMHI is predicting above-average rainfall to continue for three to four weeks in Ecuador. The coastal area will receive the heaviest rains, it says, but the sierra region will also be affected.

Olmedo explains that El Niño is a widespread event in which water temperatures increase over thousands of square kilometers of the equatorial Pacific Ocean. “What we are experiencing is a much rarer event where the water temperatures rise within a few kilometers of the shore, providing the moisture and energy for strong localized storms within an area of several hundred miles. An El Niño can affect weather worldwide.”

The phenomenon has a name, Olmedo says. “It’s called El Niño Costero (coastal child) and we have only experienced it two other times within the past 50 years,” he says. “This is the strongest of the three.” At one point in mid-March, offshore water temperatures rose to five degrees celsius above normal.

There is good news, according to INAMHI. Water temperatures on the coast are falling, which should reduce the severity of the storms in coming weeks. “We anticipate a return to normal water temperatures by late April or May,” a INAMHI statement said. “This will coincide with the end of the rainy season.”

Rainfall in Cuenca has been about 40% above normal since January, INAMHI reports. Some areas of Ecuador, particularly on the coast, have received 200% to 300% normal rainfall. Peru has experienced the worst of El Niño Costero, where flooding has made thousands homeless and killed a 125.