AKB48 plans to hold their 49th Single General Election on 17 June 2017 at Toyosaki Villa SUN Beach in Okinawa, the outdoor venue's capacity can hold around 10,000 fans, but bad weather hits Okinawa, and it may come heavy rain, thunderstorms and strong wind. For fans safety, the management may move the event into an indoor venue nearby: Okinawa Citizens Hall where the main hall can host around 800 fans. AKS will make the decision on 16 June 2017 morning.

Note: If all Okinawa Citizens' facilities is opened for the event, it can hold 1,800 fans.

Reference: Sponichi Annex
http://www.sponichi.co.jp/entertainment/news/2017/06/16/kiji/20170616s00041000039000c.html