Why haven't we heard anything about New Orleans' mesh networking system they purchased before the hurricane? These ad hoc p2p networks do not rely on cell towers, but use individual devices as routers and relay points.
If disaster cripples existing communications networks (including other wireless networks) these networks and devices will still operate. They can also transmit video, and thanks to a snappy algorithm, have location tracking = GPS on steroids. (Inside buildings, altitude included)