An app that has been used to connect with people during the hurricane is Zello. 

Zello essentially acts like a walkie-talkie and allows users to send voice messages in real time to anyone listening to a channel.

However, contrary to false rumors spreading online - it requires Internet access via Wi-Fi or a cellular data network to work.

So the bottom line is: if Zello works, chances are so will your cellphone. However, group messaging capabilities can be superior to simple text messaging.

So why use it?

Zello is different to messaging apps because people don't need to dial a phone number, or send a text. Instead they touch and hold an "echo" button to speak to each other live, and groups of up to 2,000 people can be created.