8 November 2021

Mallama: a deadly landslide in Colombia on 2 November

Posted by Dave Petley

Mallama: a deadly landslide in Colombia on 2 November

On 2 November 2021 heavy rainfall triggered a deadly landslide in the village of Mallama in Nariño Province of Colombia, killing 17 people and injuring a further nine.

The best image that I can find that provides a good view of this failure is on the Nariño Government website:-

The 2 November 2021 landslide at Mallama in Colombia, which killed 17 people.

The 2 November 2021 landslide at Mallama in Colombia, which killed 17 people. Image via the Gobernacion de Nariño.

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Based on this image this is a failure in deeply weathered regolith on a very steep slope.  It appears to have demolished a number of houses.  This is probably best characterised as a debris avalanche, although with a comparatively moderate runout distance.

RCN Radio has this very dramatic image of the aftermath of the landslide from a different perspective:-

The aftermath of the 2 November 2021 landslide at Mallama in Colombia.

The aftermath of the 2 November 2021 landslide at Mallama in Colombia. Image by JHR Ingeniería via RCN Radio.

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According to news reports, the site had not previously been identified as being at risk of landslides, and the reason for the failure at this time is not clear.  There is however a risk of further failures that will necessitate the relocation of people whose houses are as yet undamaged.