Cities like Chofu have notification services to Keitai mail that inform you local security information including blackout schedules, but few have Twitter accounts. Chofu Anzen Tweet is an unofficial Twitter account that tweets the same information which was converted by a tiny service running on Heroku. Presented at Tokyo Rubyist Meetup held on Apr. 20th 2011 http://www.tokyorubyistmeetup.org/events/110-after-the-earthquake