30 September 2019
Kerala – satellite images of the landslides from the summer monsoon
As the 2019 summer monsoon draws to a close (although some areas continue to be affected by heavy rainfall), cloud is starting to withdraw, providing opportunities to view the landslides that have been triggered by the heavy rainfall in Kerala in August. A week or so ago, Raj Bhagat Palanichamy tweeted some images from Copernicus Sentinel showing some of the landslides. I have looked at the Planet Labs imagery – some of these landslides are now becoming visible too. The image below shows a set of landslides in the area of Amarambalam (these landslides are in the vicinity of 11.31, 76.48) for example:-
These landslides appear to primarily be shallow slips in weathered materials that have transitioned into channelised debris flows. One of the landslides is quite large:-
The most serious landslide occurred at Kavalappara in Wayanad, where up to 59 people were killed in a major landslide. Unfortunately, this site has yet to be imaged clearly. However, in the area of Portimund Lake, to the east of the images above, another large landslide can be seen in the Planet Labs images:-
These are typical landslides triggered by exceptional rainfall in hilly terrain. The resultant flows along the channels can be devastating to anything in the path. As rainfall intensities continue to increase, and the upland environment is further damaged by human activities, we will see increased occurrence of these types of mass movements across South Asia, with devastating effects.
Planet Team (2019). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/