Perhaps this is bigger than an app, but an app might be a part of it: let the citizens be able to deploy a Mesh Network of Wi-Fi access points that would join the city's emergency internet backbone or route around it if it is down. Ideally, we'd be able to re-purpose existing wi-fi hardware to do so. Wifi was a big part of relief in Haiti and it could be just as useful here for coordinating resources from the ground up.
Idea No. 11