During the Atlanta ice event that stranded 1000's of people around town, people were trying to both post shelter locations and requests for aid (stranded) via various methods. The one that was probably more popular, but mostly useless was the Google map location app (via Facebook).
Pins with no descriptions, folks not able to read without accounts (when they tried to use Yahoo), etc.
Request - Create an app that allows better detail to be enabled in areas during disaster to request aid or post location of shelters AND is not completely controlled by local authorities. Search for Snowedoutatlanta and you can see how the effort started on Facebook and then got so big it created regional help groups. But, there is no good app for that...