Overall Green alert Flood
in Tonga

Flood impact summary

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

Updated: this report is based on update 3: (16 Feb 2018 17:51) .

GDACS ID: 1000167
Deaths: 1
Displaced: 4500
Region: Administrative unit not available
Locations: Tropical Cyclone GITA passed near the islands of Eua (pop. 4 900) and Tongatapu (pop. 74 600) (Tonga) on 12 February and it passed approx. 50 km south of Ono-I-Lau (Fiji) and 200 km south of Kandavu island (Fiji) on 13 February.
Known identifiers for this event:


For more info on GDACS alert score click here.

Impact Assesement as of 11-02-2018

Satellite Observation


Timeline of revisions

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

IDAlert ColorPopulation affectedSourceDate added
1 1 killed and 4000 displaced JRC 14 Feb 2018 11:21
2 1 killed and 4000 displaced JRC 14 Feb 2018 14:50
3 1 killed and 4500 displaced JRC 16 Feb 2018 17:51

Flood polygons

This polygon (translucent blue with a blue border) is drawn by the analysts recording the flood event. It is meant to include all the areas reported as affected, by official source or the media. It does not represent the area actually under water.

Microwave flood detection

Flooded area, as detected in microwaves by the Global Flood Detection System of the JRC, based on NASA TRMM/GPM observations. This system has a rather low resolution (of 5-10km) but is not affected by clouds.
For more details, see http://www.unisdr.org/files/9622_LBNA23303ENC002.pdf.
The areas with a flood signal along the coast are an artefact of the system and should not be considered.

Optical Flood detection

Flooded area as detected in optical wavelengths by NASA/MODIS, known as "MODIS Flood Product". Data are made available by NASA GSFC Flood Mapping Project, http://oas.gsfc.nasa.gov/floodmap/index.html. Resolution of 250m, heavily affected by cloud cover.