You've probably seen or heard something about a messaging app called Zello the past few days. It's billed as a 'walkie-talkie' app where people can communicate with each other during a natural disaster or other event that affects internet data connections.

Zello has been around for several years but since Hurricane Harvey the number of downloads have quadrupled or more. Zello claims in just the past few days over 1-million people downloaded the app and it currently sits atop the most downloaded app rankings in both iTunes and the Google Play Store.

What does it do?

Zello is ridiculously easy to use. To send a voice message you tap on your contact then on a large circle that takes up almost all of the space in the opened app. When you you tap the circle you're recording a message. It's sent immediately to your contact who can listen now or later when they log onto the app. The communication reminds me more of a text message than phone call. It really is like you're talking to them on a walkie-talkie.

People and organizations can create groups or channels where the messages go out to only people who are following the group. Friday afternoon I found a Hurricane Irma South Florida group with several hundred members. Listening to that channel is a lot like listening to an old CB radio. Those conversations are moderated by someone in the group and if anyone connects to share some nonsense or to troll on the group, the moderator will kick them out so they cannot listen in on the group again.

While I listened to this channel I heard people asking questions about road closures, whether pets can be taken in with their owners at an emergency shelter (they can) and whether hotels are required to take pets (they are.)

I imagine a Zello channel like this is invaluable when someone can't access tv or the internet.

I also sent messages back and forth with one of my friends who lives in Jacksonville, Florida and we chatted about what she was doing to protect herself and whether she was going to try to get out of town before the storm hit. I could have done that with a phone call but through a Zello message I knew I wasn't going to be catching her at a bad time and I knew she would hear the message and could respond when she had a moment.

A downside that everyone seems to point to is that Zello requires a wi-fi or cellular data connection to work. "It's useless when my power goes out," is what a buddy of mine said when I asked him about using the app.

While it is true you can't send Zello messages with no data internet connection it may not be the big deal you'd think. While cell towers do go down in natural disasters most often they are just overwhelmed. Everyone wants to get on the internet or make phone calls when the power goes out and if every single person is using cellular connections, there's only so much data the cell towers can handle. Have you ever tried browsing or posting to Facebook at a large football game?

Zello uses very little bandwidth to get those messages out. Its developers claim it's such a small amount of bandwidth that Zello messages will slip right through while other connections are lost. Which makes sense. Plus, if your message isn't able to get delivered immediately, it will get to your friend and they can listen and respond when they're able to get an internet connection.

Two things you do need to know if you download the app. Zello uses a lot of battery power if you're listening or monitoring a channel. A long conversation with a friend will also drain the battery faster. For that reason you don't want to have it on all the time.

The other thing is that to use Zello you're limited to staying in touch with 5 contacts. The app is free for up to five contacts but if you want to add more, there's a $6/month charge. There is no commitment though, so you don't have to pay for a year or 6 months, just pay the $6 when you know you need to use the app instead of text messages or Facebook Messenger.