Satellite Detected Waters Extent in Tomasina Districts, Atsinanana Region, Madagascar

This map illustrates satellite-detected water extent as of 07 January 2018 over Mananjary district, Vatovavy-Fitovinany region, in Madagascar as detected by Sentinel-1. ~ 1000 ha of land over the communes of Tsiatosika and ~1300 ha in Ankatafana seem to be inundated. These zones are mainly agricultural and/or swamps. These waters are the results of recent heavy rains following the cyclone AVA-18 which made landfall the 05 January 2018. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas, due to the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

This map illustrates satellite-detected water extent as of 07 January 2018 over Vohipeno & Manakara Atsimo districs, Vatovavy Fitovinary Region, in Madagascar as detected by Sentinel-1. As of 07 January 2018. Several communes of these districts seem to be affected by inundations due to to the heavy rains that have followed the cyclone AVA-18. ~1,000 ha of lands appear to be likely affected in Vohitrindry, ~ 800 ha in Lanovo and ~400 ha in Vohilany communes. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas because of the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR UNOSAT.

This map illustrates satellite-detected water extent as of 09 January 2018 over Soaneriana Ivongo district, Analanjirofo region, in Madagascar as detected by Radarsat-2. Limited standing waters can be observed in the area. These zones are mainly agricultural and/or swamps. These waters are the results of recent heavy rains following the cyclone AVA-18 which made landfall the 05 January 2018. It is likely that flood waters have been systematically underestimated along highly vegetated areas along main river banks and within built-up urban areas, due to the special characteristics of the satellite data used. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR-UNOSAT.

**UNOSAT code: TC20220221MDG** This map illustrates satellite-detected surface waters in Vangaindrano district, Atsimo Atsinanana region, Madagascar as observed from a Sentinel-2 image acquired on 1 March 2022 at 10:00 local time. Within the analyzed cloud free zones of about 300km2, a total of about 25 km2 of lands appear to be flooded. Based on Worldpop population data and the detected surface waters, about 5,500 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).

**UNOSAT code: TC20220221MDG** This map illustrates satellite-detected surface waters in Vangaindrano district, Atsimo Atsinanana region, Madagascar as observed from a Sentinel-2 image acquired on 24 February 2022 at 10:00 local time.  Within the analyzed cloud free zones of about 300km2, a total of about 56 km2 of lands appear to be flooded. Based on Worldpop population data and the detected surface waters, about 12,500 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).

**UNOSAT code: TC20220201MDG** This map illustrates satellite-detected surface waters in Farafangana district, Atsimo Atsinanana region, Madagascar as observed from Sentinel-1 image acquired of 15 February 2022 at 05:12 local time. Within the analyzed area of about 1,200 km2, about 6 km2 of lands appear to be flooded. The water extent appears to have decreased of about 87 km2 since 8 February 2022. Based on Worldpop population data and the detected surface waters, about 1,200 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 UNITAR-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.