Mudslide in Colombia Sweeps Through Town, Heavy Rains May Portend El Niño

Coastal El Niño impacting Peru–and now perhaps Colombia–may predict a stronger El Niño later this year.

Residents of a Colombian city were awakened by an alarm that warns them of impending disaster Friday night.

Many in the small town of Mocoa were sleeping and did not have time to evacuate to higher ground, and were swept away by an enormous mudslide after heavy rains caused a nearby river to overflow. The surge of mud killed and injured hundreds and destroyed many homes.

At least 234 died, and 220 were missing in the city of about 350,000. Hospitals struggled to cope with the burden of so many injuries, and some with more serious wounds had to be airlifted to other towns.

Houses in 17 different areas were buried or taken away by the landslide, according to Mocoa’s mayor, José Antonio Castro.

A man looks at a destroyed area after heavy rains caused several rivers to overflow, pushing sediment and rocks into buildings and roads in Mocoa, Colombia, on April 1, 2017.
PHOTOGRAPH BY JAIME SALDARRIAGA, REUTERS

In early March, unprecedented rainfall brought extreme flooding to Peru, leaving 94 dead and almost a quarter of a million without homes so far. Evacuations are still underway, with heavy rainfall expected to continue. (Watch a woman emerge from floodwater in Peru after being swept away.)

The southwestern Colombian town of Mocoa is close to the border of Ecuador and is considered part of the equatorial region most affected by changing weather, along with Peru.

LA NIÑA, EL NIÑO, OR NEITHER

La Niña conditions, which typically are dry and bring cooler than average sea surface temperatures to equatorial regions, were expected to persist through February, with conditions returning to normal for the spring.

As of March 9, NOAA determined that conditions would reflect neither El Niño nor La Niña temperatures, calling the current weather patterns “El Niño Southern Oscillation (ENSO) neutral.”

Yet Peruvian authorities have blamed the flooding on El Niño, calling the events the worst El Niño-related flooding in recent history. So how can normal sea surface temperatures—and what should be relatively mild conditions—affect the equatorial region of South America so dramatically?

The answer is somewhat complex.

Ocean waters are currently warmer than usual off the coast of Peru. Warmer equatorial waters mean El Niño conditions, but because these warmer temperatures are so localised, officials have not yet declared an official El Niño event.

Average Sea Surface Temperature (SST) anomalies for the week of February 1, 2017. Anomalies are computed based on the 1981-2010 base period weekly means.
GRAPHIC COURTESY NOAA/NATIONAL WEATHER SERVICE

To explain the flooding, Peruvian climate scientists are calling this particular occurrence a coastal El Niño, a mini version of the larger phenomenon that affects the entire Pacific.

The region of Colombia impacted by flooding is in a similar coastal region just north of the Peruvian Coastal El Niño–one that is also experiencing warmer-than-usual temperatures.

The coastal El Niño could portend a more severe El Niño weather pattern later in the year, or it could potentially be the result of broader changes in a changing climate. 

CHANGING WEATHER PATTERNS

Climate change has had a significant impact on the global average sea surface temperature, with an increase of more than 1.5 degrees Fahrenheit since 1901, according to the EPA.

This graphic shows a one- to three-degree Fahrenheit change in Sea Surface Temperature (SST) over the period between 1901 and 2015.
GRAPHIC COURTESY IPCC/NOAA/EPA

The increase in temperature may have brought on heavy rains and flooding in the region, which, many say, indicates a stronger El Niño later in the year.

Header Image: An aerial view of the deadly landslide that followed heavy rains in Mocoa, in the Putamayo region of south-west Colombia, on April 1. PHOTOGRAPH BY COLOMBIAN ARMY, HANDOUT, ANADOLU AGENCY, GETTY IMAGES

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