Flood warnings have been issued for many areas in Kumamoto. For details, see the screenshot, which is of a Google translation of a message sent out via the prefecture’s e-mail warning system.

http://www.anshin.pref.kumamoto.jp/rireki/saigai/430000.html

I’ve come to the conclusion that the most reliable way to get disaster information, even if you don’t understand Japanese, is to sign up for the Japanese e-mail warnings at the following address:

http://www.anshin.pref.kumamoto.jp/

If you can’t read the Japanese on this page, just send it through Google translate or a similar site:

https://translate.google.com

Then, when you get a message in Japanese from the prefecture, run it through Google translate. It would be nice if the prefecture could set up a system to do this automatically but, well, I wouldn’t hold my breath.