Copernicus Sentinel-1 images show the impact of the dam failure on the Xe-Pian Xe-Namnoy lake area in the southeastern province of Attapeu in Laos.
The flood seems to have been caused by a breach in another saddle dam (not the main dam) following heavy rainfall. The effects of this can be seen clearly at larger scale, with the flood following the Vang Ngao river down to the villages. This is shown in the animation here.
Sentinel-1’s radar ability to ‘see’ through clouds, rain and in darkness makes it particularly useful for monitoring floods. Images acquired before and after a flood offer immediate information on the extent of inundation and support assessments of property and environmental damage.
The C-band synthetic aperture radar on Sentinel-1 can provide large swath images with a resolution of 20 m and within hours of acquisition to aid emergency response.