For building resilience against water-related disasters



Global Flood Alert System Ver.2.2 (GFAS-II) produced by IDI-Japan made it possible to display the area of observed rainfall and the *1) probable maximum precipitation (PMP) at designated time with an interval of one hour in visually intelligible form, classifying the data by 5 ranked different probabilities in a 10km Mesh Global Atmospheric Model, using GSMaP rainfall data provided by JAXA.

Thereby, GFAS-II is capable of displaying the probable maximum precipitation as flood risk index by using near real-time rainfall data obtained within as little as 1 hour. The display range of those data covers most of all countries and regions in the world.

In the revised version of GFASⅡ released in June, 2020, area coverage partially expanded in the areas of Europe, Africa and America by the expansion of GSMaP coverage. Furthermore, it became possible to display the past precipitation and probable maximum precipitation data with ranked categories, going back to a certain day within one-year.

Operation Policy for this GFASⅡ website can be referred to “About GFASⅡ” in the bottom right corner of the screen on the top page.

*1) The theoretically greatest depth of precipitation for a given duration that is physically possible over a particular drainage area at a certain time of year; in practice, this is derived over flat terrain by storm transposition and moisture adjustment to observed storm patterns. Source:“”
URL for GFASⅡ Revised Version(ver.2.2) is shown below(since June, 2020)  (for PC)  (for Smartphone)


If you have any questions, please send an e-mail to the following address:

Infrastructure Development Institute(IDI-Japan)