Satellite Detected Surface Waters in Maroantsetra area, Analanjirofo region, Madagascar

This map illustrates satellite-detected flood waters extent and evolution between 08 and 10 March 2017 over Maroantsetra area, Analanjirofo region in Madagascar as detected by TerraSAR-X radar images acquired on 10 and 08 March 2017. Between 08 and 10 March 2017 and within this map extent, waters receded from about 4,270 ha of lands. Many areas within this zone remain affected and ~6,230 ha of lands were still flooded on the 10 March 2017 whereas ~10,500 ha of lands were flooded the 08 March 2017. It corresponds to about 40% decrease. 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.

This map illustrates satellite-detected water extent as of 10 March 2017 over Antsahanoro commune, Antalaha district in Madagascar as detected by TerraSAR-X. As of 10 March 2017, ~ 335 Ha of land over Antsahanoro commune seem to be inundated and have experienced an increase of standing waters. These zones are mainly agricultural and/or swamps in the commune of Antsahanoro. These waters seem to be the results of the recent heavy rain related also to the cyclone ENAWO-17 which made landfall the 07 March 2017. 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.

**UNOSAT code: TC20250308MDG, GDACS ID: 1154** This map illustrates the potentially affected cropland in Maroantsetra District, Analanjirofo Region, Madagascar, based on RCM-2 satellite images acquired on 9 March 2025. In the analyzed area of approximately 1,200 km², about 140 km² of cropland is identified, of which about 35 km² appears to be affected by floodwaters. This is a preliminary analysis and has not yet been validated on the ground. Ground feedback is requested and can be sent to the United Nations Satellite Centre (UNOSAT). Important Note: Flood analysis based on radar images may underestimate the presence of standing water in built-up or densely vegetated areas due to the backscattering properties of the radar signal.

This map illustrates satellite-detected water extent as of 07 January 2018 over Toamasina districts, Atsinanana Region, in Madagascar as detected by Sentinel-1. Some standing water areas could be observed north and south of Toamasina, mainly in the agricultural and/or open areas along the river. It is likely that floodwaters 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 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.