Heavy rains cause devastating landslides in Colombia

The landslides that began in the early morning of April 1 in the Amazonian region of Colombia were caused by unusually intense rains and by the overflow of the Mocoa, Mulato and Sangoyaco rivers. The town of Mocoa has been almost completely buried, thousands of people have been affected in different municipalities and find themselves without drinking water or electricity, hundreds of homes have been destroyed and the Colombian Government has officially registered 254 dead until 3 April.

Omar Franco, director of the Institute of Hydrology, Meteorology and Environmental Studies of Colombia (Ideam), warned that, as of 3 April, more than 500 municipalities are at risk of landslides. Of these, 182 have already orange to red alert. The causes are diverse and are linked to extreme weather events, combined with deforestation and inadequate and clandestine land use.

Franco explained that March was an atypical month and the rainiest of the last six years. For example, when reviewing precipitation data from the municipality of Mocoa, it was established that the rainfall level reached 129 millimeters. Of these, 80% fell for only three hours, from 11:00 p.m. to 1:00 a.m., which explains in part the tragedy that occurred. This municipality has presented similar levels of precipitation but distributed over 24 hours.

For his part, the director of the Corporation for Sustainable Development for the South of the Amazon, Luis Alexander Mejía, indicated that improper use of the soil aggravates this type of event. Apart from the heavy rains, one of the causes of the avalanche is deforestation. The department of Putumayo precisely became the fifth department of Colombia with more loss of vegetation because 9,000 hectares were deforested until 2015 and the devastation continued to accelerate to obtain arable land not authorized by the Government. Mejía recalled that in this area 15% of the soils already suffer erosion and some 10% severe  erosion. He also recalled that these Amazonian municipalities must update their land management plan.

Ideam invited local authorities and Colombians in general to exercise permanent monitoring over their territory, especially in micro-watersheds, because they can identify the sudden growth of rivers. In Colombia there are more than 700,000 rivers and bodies of water so it is impossible to have monitoring stations in each one of them.

The departments of Antioquia, Cundinamarca, Valle del Cauca, Cauca, Tolima, Putumayo and Nariño represent the greatest risks at this time. In terms of rivers, the main risks are associated with the upper Cauca River and the middle part of the Magdalena River.

"Climate variability and climate change will continue to produce rain and drought," Franco said, adding that Colombian municipalities should review and update their risk maps, "but prevention is the most important thing," he concluded.