TAMPA -- Zello has become a popular app in the wake of Hurricane Irma and has shot to the number one spot on iTunes.

The app has gained popularity for its ability to connect with people without phone numbers. Many volunteers and first responders on the scene after Hurricane Harvey in Texas used it to connect with people who needed to be rescued.

As awesome as this app already sounds, there is a catch.

The Zello app can not function without cellular data service or an available internet connection on your cell phone.

As much of a handy tool as Zello's app may seem, it is best to be fully prepared in the case that wifi or cellular data is not available.

For more information, check out our news partners at the Tampa Bay Times.