Overall Green alert Flood
in Japan

Flood impact summary

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

GDACS ID: 1102213
Deaths: 3
Displaced: 40
Region: Fukushima Prefecture, Ibaraki Prefecture, Chiba Prefecture, Mobara, Kitaibaraki, Hitachiota, Otaki
Countries: Japan
From - To 08 Sep - 11 Sep
Known identifiers for this event:


For more info on GDACS alert score click here.

Impact Assessement as of 11-09-2023

SENDAI Indicator A N Country Location Info
death 1 Japan Kitaibaraki
death 1 Japan Hitachiota
death 1 Japan Otaki
SENDAI Indicator B N Country Location Info
affected 1 Japan Hitachi
displaced 40 Japan Mobara
SENDAI Indicator C N Country Location Info
houses 1204 Japan Fukushima Prefecture
houses 700 Japan Ibaraki Prefecture
houses 225 Japan Chiba Prefecture

Satellite Observation

Satellite-based Flood extent provided by GLOFAS
Overall of the satellite-based flooded area from / to : 2023-09-01 / 2023-09-18  

Timeline of revisions

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

IDAlert ColorPopulation affectedStart DateEnd DateSource
1 3 deaths and 40 displaced 08 Sep 2023 11 Sep 2023 GLOFAS

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.