Satellite Detected Water Extent in Khongxedone District, Salavan Province, Lao PDR

This map illustrates the satellite-detected water extent in the District of Sanamay, Attapeu Province, in the southwestern part of Lao People's Democratic Republic after the tropical storm SONCA-17. The UNITAR-UNOSAT analysis used a Sentinel-1 satellite image acquired on the 30 July 2017 and detected several areas with potentially standing waters. In the district of Sanamxay ~5,225 ha are likely flooded.This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

This map illustrates the satellite-detected water extent in the Phonhong & Viengkham Districts, Vientiane Province, in the northwestern part of Lao People’s Democratic Republic after the tropical storm SONCA-17. The UNITAR-UNOSAT analysis used a Sentinel-1 satellite image acquired on the 1 August 2017 and detected several areas with potentially standing waters. In the district of Phonhong 2,045 ha are likely flooded and in the district of Viengkham 1,077 ha. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

This map illustrates the satellite-detected water extent in the district of Khamkeuth in Borikhamxay province, in the central-northern part of Lao People’s Democratic Republic after the tropical storm SONCA-17. The UNITAR-UNOSAT analysis used a Sentinel-1 satellite image acquired on the 11 August 2017 and detected several areas with potentially standing waters. In the district of Khamkeuth ~2,441 ha are likely flooded. Kindly note, the district of Khamkeuth has been partially analyzed due to the image does not cover the full district. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

**UNOSAT code: FL20190905LAO** This map illustrates satellite-detected surface water in Salavan provinces of Lao PDR as observed from Sentinel-1 imagery acquired on 10 September 2019. Within the analysed extent of about 4,000 km2, a total about 4 km2 of land appear to be flooded as of 10 September 2019. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR - UNOSAT. Important Note: Flood analysis from Sentinel-1 imagery acquired on 10 September 2019 may seriously underestimate presence of standing flood water in built up areas due to backscattering of the radar signal

**UNOSAT code TC20220928LAO, GDACS Id: 1000922** This map illustrates satellite-detected surface waters in Khongxedone District, Saravan Province & Sanasomboon, Champasak Province, Lao PDR as observed from a Sentinel-1 image acquired on 1 October 2022 at 05:45 local time. Within the extent of this map of 600 km2, about 14 km2 of lands appear to be flooded. Based on Worldpop population data and the detected surface waters in the map extent, about 1,800 people are potentially exposed or living close to flooded areas. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to United Nations Satellite Centre (UNOSAT). Important note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to backscattering properties of the radar signal.

**UNOSAT code: FL20190905LAO** This map illustrates satellite-detected surface water in southern provinces of Lao PDR as observed from Sentinel-1 imagery acquired on 6 September 2019. Within the analysed extent of about 60,000 km2, a total about 1,000 km2 of land appear to be flooded as of 6 September 2019. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT. Important Note: Flood analysis from Sentinel-1 imagery acquired on 6 September 2019 may seriously underestimate presence of standing flood water in built up areas due to backscattering of the radar signal