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Colombia: Floods related to La Niña - Emergency Plan of Action (EPoA), DREF Operation n° MDRCO018

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A. Situation Analysis

Description of the disaster

The CRCS´s has formulated this Emergency Plan of Action plan to prepare and respond to the likely effects by the 2021 La Niña phenomenon in the country. This plan prepared by CRCS is a preventive activation plan, which means it consist of activities that the National Society will carry out prior to the potential emergency to be ready to respond immediately when the event occurs.

La Niña is a phenomenon composed by both, positive weather anomalies in some places and negative weather anomalies in others. In Colombia, the positive anomalies usually manifest as an increase in rainfall in the Andean, Caribbean, and Pacific regions, as well as the Plain Foothills of the Eastern Plains. While the negative anomalies present by a decrease in the sea surface temperatures in Eastern regions of the Orinoquía and Amazonia. However, while certain events and impacts are expected to occur, exceptional events may happen as well. For example, in 2010, there were slight precipitations in the centre and southern areas of the Orinoquía region.

According to the National System for the Prevention and Attention of Disasters (SNPAD), between 6 April to 10 November 2010, the rainy season associated with La Niña, left 1,170,480 people affected in 549 municipalities, 28 departments and the Capital District of Bogotá. A total of 117 people died, 191 were injured and 20 were missing. A total of 1,654 homes were destroyed and 196,662 were damaged. Of those, 94 per cent of the injured people and 95 per cent of the damaged houses were directly affected by the floods. The most affected departments by the rainy season were as follows: Bolívar, Magdalena, Córdoba and Sucre. This experience shows the historical impacts La Niña has had, especially on shelter and the importance of using forecast information available to better prepare for an early response to this phenomenon.

As reported by the Colombian Meteorological Service (IDEAM), in its climate forecast bulletin N°11, published in November 2020, La Niña conditions are currently present in Colombia. Therefore, it is estimated that within the following months, since December 2020 until March of 2021, rains will be above historical values in ample sectors of the Caribbean, Andean, Pacific and Orinoquía regions. Compared to the 2010, events in 2021 unexpected events are likely to happen in a similar fashion.

The probabilities of the cooling in the equatorial Pacific Ocean range between 85 per cent and 90 per cent. The persistence of these climate conditions favours La Niña phenomenon, which is likely to remain in 2020 and during the first part of 2021. The extreme temperatures in November fluctuated between 3° to 10° degrees Celsius, which reiterates the continuity of this phenomenon. Particularly in the Caribbean insular area, higher than normal rainfall of up to 40 per cent is expected. Similarly, in the Andean, Pacific, Orinoquía and the northern Amazon region, rainfall increases up to 60 per cent are expected.

January is usually a time in which, compared to previous months, precipitation volumes significantly decrease in most regions of Colombia. In January and February 2021, however, rainfall excesses of up to 50 per cent are forecast for a large part of the Caribbean region, northern Pacific, Andean region, and central west of the Eastern Plains. For the rest of the country, an increase of up to 40 per cent in heavy rains is expected.

According to IDEAM climate forecast (both deterministic and probabilistic), published in its report No. 11 (20 November 2020) (see figure 1) there is a 97 per cent to 100 per cent probability that a colder season will arise in the first quarter of 2021. This season may be linked to the first rainy season, which is due to start in March 2021.