The idea of a functional warning system gained traction with consumers after April's tornadoes, as private companies rushed to fill the safety gap left open by government.
At the end of the Cold War, many of the civil defense sirens designed to warn of disaster were neglected and eventually abandoned. The only warning for some residents on April 27 was the thundering noise of an approaching tornado.
A renewed demand for severe-weather alerts has driven private companies to create alerts in the virtual world and send them to consumers individually.
Emerson Russell, owner of Chattanooga-based ERMC Security Solutions, is offering severe-weather alerts nationwide to his commercial and residential customers free of charge.
"We just feel this is an added safety feature for the community, to give the residents extra protection," Russell said.
In place of the familiar wail of an air raid siren, ERMC subscribers will receive warnings on their security keypads that are sent out through the cellular GSM network, company sales manager Jim Zink said.
The same technology also supports home automation, including the ability to lock a door from a cell phone or monitor the babysitter on an iPad.
"We can pull up customers in a particular ZIP code and dispatch an automated warning to their keypad," he said.
Tens of thousands of Russell's customers will have access to the same system that Zink says saved a man caught in the recent Joplin, Mo., tornado.
"He got out of the shower, heard his keypad beeping, saw the alert and got to safety five minutes before the sirens went off," Zink said.
The alerts are keyed in to multiple types of natural disasters, from hurricanes and tsunamis to fire and flash floods, he says.
But for those without the roughly $2,000 needed to automate a home, Todd Jones, founder of Firecracker Media, has another solution.
Called The Messenger Dog, Jones charges municipalities a flat rate for the ability to push text messages out to students, teachers, parents and anybody else who opts in.
Jones thought of the idea when, as a swim coach, he needed a way to quickly tell parents that practice was canceled for the day.
"Some people are driving from 20 minutes away, and if they walk in and there's a sign on the door, boom, they're (upset)," he said.
During north Georgia's April storms, school officials in Murray and Catoosa were able send out emergency messages to residents, coordinating their responses with rescue officials via text, which is more reliable than voice service when cell towers are down, he said.
While his system is gaining acceptance, he's still struggling to expand to more school districts and connect with police, who could use the system to warn of escaped convicts or teenage abductions.
"They usually say, 'We're doing fine without it,' and that's because it's new," he said.
But once schools get it, they get hooked, he said.
He said Murray County schools send an average of 30,000 texts per month.