A walkie-talkie app is helping people get through hurricanes

As Hurricane Irma flooded the streets of Miami on Sunday afternoon, voice after voice beeped to life in a Miami channel on the walkie-talkie app, Zello.

One person said his food was wet, and asked if anyone might come help him evacuate. Another said he was compiling a database of people with boats and others willing to volunteer to any rescue effort. Others asked simple questions such as, "what category is the hurricane?" and "how's everybody doing in Miami?"

Zello is a free app that works like a walkie-talkie, if your walkie-talkie had much wider range. Using cell service and Wi-Fi, the app allows people to beep into a wide-ranging conversations. Some of those conversations are centered on geographic areas such as Miami, around which people seemed to be coordinating rescue efforts amid the rising floodwaters of Hurricane Irma.

Zello has around 100 million users, many of them outside the United States, but it gained significant attention inside the U.S. in late August and early September amid a different devastating storm.

As Hurricane Harvey dumped unprecedented amounts of water on Houston and surrounding parts of Texas during August's closing days, Zello users -- including the famous makeshift rescue group called the "Cajun Navy" -- used the app to figure out who had a boat or a jet ski and where to send them.

Volunteers used Zello to compile addresses of people in need of rescue, and talked with others on the app to figure out who had been rescued and who still needed help to evacuate.

Six million people have signed up for Zello since Hurricane Harvey, according to Alexey Gavrilov, the company's founder and chief technology officer.

The influx of new users amid devastating storms has led to long hours at Zello over the past few weeks, but Gavrilov said they managed to keep the app humming but for a few blips. The company added 21 new servers last week, and they've tried to tamp down rumors that Zello would work even without access to the internet.

That should be encouraging to folks in Florida who won't necessarily be able to rely on cell service to get whatever help they need. They will, however, need their cell phones if they want to use Zello. As the flooding worsened in Miami on Sunday afternoon, it seemed every third or fourth user in one Irma-related channel urged people to turn off their phones to conserve battery for later, when they might need it most.