This map illustrates the satellite-detected surface waters extent in Sanamxay district, Attapeu province, as observed from the Radarsat-2 radar image acquired on 24 July 2018. The previous day, the Xe-Namnoy dam collapsed, inducing flash floods along the Vang Ngao river and affecting several villages located 50 km downstream. Within the analysed area 14,692 ha of surface waters were detected after the heavy rains that happened on 22 July and as well the collapse of the dam. Several villages and surrounding agricultural fields seems to be inundated. The villages of Ban Hinlat, Ban Thaseangchan, Ban Mai and Ban Samong-tai seems to be the most affected ones. It is likely that flood waters have been systematically underestimated along highly vegetated areas, along the main riverbanks and within built-up urban areas because of the special characteristics of the used satellite data. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT.