14 July 2022
San Antonio de Prado: a high mobility landslide in Colombia
Posted by Dave Petley
San Antonio de Prado: a high mobility landslide in Colombia
On Wednesday 13 July 2022 a major landslide occurred at San Antonio de Prado in Medellin, Colombia, killing at least two people. Videos of the event have been circulating on social media. For example, this news report on Youtube shows a slice of the rear scarp failing and then transitioning into a mobile flow, whilst from about 40 seconds it shows a different angle of the flow event:-
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Later in the video there is drone footage of the aftermath, and some segments showing the impacts on the channels downstream.
El Colombiano has this image of the aftermath of the landslide, showing the landslide source and much of the long debris train:-
The aftermath of the 13 July 2022 landslide at San Antonio de Prado in Colombia. Photo by Manuel Saldarriaga via El Colombiano.
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The location of the landslide is, I believe, 6.196, -75.658:-
Google Earth image of the site of the of the 13 July 2022 landslide at San Antonio de Prado in Colombia.
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It is interesting to note that the most recent Google Earth imagery, from November 2021, shows the site of the landslide to have been forested. The area around the landslide site appears to have suffered from landslides in the past, and the geological maps of the region mark much of this area as being slope deposits.
News reports indicate that the local communities had been concerned that a failure was developing on the hillside prior to the landslide. Infobae has a report (in Spanish) that highlights that a failure had developed over several months, and that Medellin Council was warned of the risks on 29 June 2022, which led to a visit by the Undersecretary for Physical Infrastructure, Adrián Alexis Correa. It appears that there are video records community leaders warning that a major landslide was possible.
But for now, there are concerns about further instability and of the implications of the damming of the channel, Quebrada Doña María. This will require attention in the coming days.
There has been heavy rainfall in Colombia in recent weeks, linked to the current La Nina conditions that are also triggering landslides in, for example, eastern Australia.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
As noted, indications of an impending landslide were noticed and reported to authorities by neighbors of the San Antonio de Prado locality. Their awareness of the kind of signs to report comes from numerous landslide experiences in this part of the Andes, recent and going back for decades. But the climate change effects in the area -increased precipitation- is increasing the landslide risk. Α difficult situation is made bad due to the lack of response by authorities to what is a ‘story of a landslide foretold’, to paraphrase the Colombian writer García Márquez. See details of locals studies that evaluated the increased risk in:
Aristizábal Giraldo et al., (2020). Rainfall-intensity effect on landslide hazard assessment due to climate change in north-western Colombian Andes. Revista Facultad De Ingeniería Universidad De Antioquia, (103), 51–66. https://doi.org/10.17533/udea.redin.20201215
As the authors say, …”The results highlight the need for studies that incorporate the scenarios of variability and climate change in the hazard assessment and land planning in the long term.”
dude… awesome vid. great sound comparison, nice short clips.