As Hurricane Irma continues its path toward Florida, the free, live voice app Zello has shot to No. 1 on the iTunes charts. That's likely because of news stories about the role the walkie talkie-like app played in helping responders and locals communicate in the aftermath of Hurricane Harvey in Texas. Channels can be set up and designated for specific purposes, allowing people to connect without phone numbers. In Houston, there were channels for the "Cajun Navy" volunteers who used it to find people in need of rescue from flooding, and for midwives who offered advice after Harvey. One thing the Zello app can't do, however, is work when there's no cellular data service or internet connection available on your smartphone. The app's official Twitter account posted today that "There is massive misinformation among users" about the app's capabilities. They followed up by writing that, "There has been some misinformation about Zello requirements. Please inform others: Zello REQUIRES Internet using either WiFi or cellular data network of at least 2G." If your phone's cellular data is not functioning due to network damage caused by the storm, and you're unable to connect to the internet via WiFi, you won't be able to use Zello to communicate. If you are in the path of Hurricane Irma, it's best to prepare, and assume that your phone or any communication apps will not work. MORE IRMA The Latest: Category 5 Hurricane Irma's path Tips: How to get ready for the coming storm As Irma Nears: Do those big construction cranes make you nervous?