GDACS is a cooperation framework between the United Nations, the European Commission and disaster managers worldwide to improve alerts, information exchange and coordination in the first phase after major sudden-onset disasters.

Overall Green Flood alert in Madagascar from 03 Mar 2012 00:00 UTC to 07 Mar 2012 23:59 UTC
GDACS Event Report - Flood impact


Flood Overview Map
Flood Overview Map. (Source: JRC)
Interactive map

This flood is expected to have a low humanitarian impact based on the magnitude and the affected population and their vulnerability.

  • Duration: 03/03/12 to 07/03/12
  • Impact: 65 killed and 0 displaced
  • Primary cause of floods: Tropical Storm Irina
  • Severity: class 1 (i.e. large flood event with significant damage to structures or agriculture; fatalities; and/or 1-2 decades-long reported interval since the last similar event)

The alert score is based on the reported death and displaced. Red = 1000 or more people killed or 800000 or more people displaced. Orange = 100 or more people killed or 80000 or more displaced.

Flood event

  • Magnitude: 6.63
  • Source: DFO DFO
  • Central Location (latitude/longitude): -18.967, 46.944
  • Date: 03 Mar 2012 to 07 Mar 2012

Satellite observations

Current surface water and potential flooded areas map (radar imagery)

The Global Flood Detection System of JRC uses passive microwave remote sensing to observe surface water for large floods. Statistical anomalies in surface water are shown as red areas, which correspond roughly to the flooded area. Extreme rainfall also causes anomalies, but is masked by the yellow layer (TRMM rainfall).

Microwave signals are not affected by cloud coverage.

Indicative flood map based on passive microwave remote sensing
Indicative flood map based on passive microwave remote sensing. (Source: JRC)

Current surface water and potential flooded areas map (optical imagery)

The Real-time MODIS Flood Map system of NASA uses optical remote sensing to observe surface water for large floods, provided there is no cloud coverage.

MODIS Automatic Flood Map
MODIS Automatic Flood Map. NASA Goddard's Office of Applied Science, in collaboration with Dartmouth Flood Observatory, is working to operationalize near real-time global flood mapping using available satellite data resources (Source: NASA)

Accumulated rain 24hrs (TRMM) map

Flash floods and landslides cannot be recorded by microwave remote sensing. These events are caused by extreme rainfall in susceptible mountainous areas. The map below shows the extreme rainfall recorded by the Tropical Rainfall Monitoring mission in the last 24h (mm/24h).

Map of accumulated rainfall
Map of accumulated rainfall. Accumulated rainfall observed from the TRMM satellite (Source: NASA)

Timeline of revisions

For accessing reports of previous advisories, please click on the advisory number in the table below.

IDAlert ColorMagnitudePopulation affectedDate added Source
1 Magnitude 6.6365 killed and 0 displaced 00:00 DFODFO
249 Magnitude 6.6365 killed and 0 displaced 200d 16:52 DFODFO
2 Magnitude 6.6365 killed and 0 displaced 454d 16:46 DFODFO

More information

Data resources

For a full list of available products related to this event, please refer to the GDACS Data Resources page.

About the data

Information related to the flood has been collected from official and media reports by the Dartmouth Flood Observatory.


While we try everything to ensure accuracy, this information is purely indicative and should not be used for any decision making without alternate sources of information. The JRC is not responsible for any damage or loss resulting from the use of the information presented on this website.