日本の大雨シーズンには、こーいう臨時の避難所を作って、電気の要らない
太鼓を使って通信するんですよね？
I think Japanese would like to prepare such temporary refuges and
install the drums to communicate without electric power
against a flood while the typhoon season!
No.714 17-08-13 臨時避難所？