As best I can tell this seems to be an extension of the warning system that has been used on radio and TV for as long as I can remember (our first TV was a black & white "portable" and we used the built-in rabbit ears). But
Salon gave some history of this that anyone familiar with the "speed" of government would have expected:
While you may not have heard about it before, this alert system is a long time coming. The mandatory system and tests originate from the Warning, Alert, and Response Network Act, signed into law by President George W. Bush in 2006, which mandated the establishment of a national wireless alerting system. The impetus came from the failures to alert citizens during Hurricane Katrina. The National Weather Service issued a warning “PERSONS…PETS…AND LIVESTOCK EXPOSED TO THE WINDS WILL FACE CERTAIN DEATH” before Katrina made landfall. The messaging was dire and clear, but the NWS lacked the ability to get this message to people’s phones—landline or mobile—as the federal government had no such centralized phone alert system at the time. The city of New Orleans didn’t have a wireless alerting system, either.
After passage of the 2006 law, local governments, states, the U.S. military, and private companies were able to use newer mass notification systems to send messages via text, email, or voice—usually voice. But those wireless alert systems lacked the engineering to alert large numbers of people simultaneously, and the cellular infrastructure was not built at the time to handle the type of volume for sending thousands of messages through the wire. Networks would crash.
Furthermore, with these legacy alerting systems, nothing was integrated, interoperable, or interconnected. Each county and state and federal agency was purchasing alerting systems in silos, and they didn’t always work with the others—even though the 2006 law had required a national wireless reporting system, not systems.
So President Barack Obama signed the Integrated Public Alert and Warning System Modernization Act of 2015, which requires these disparate alerting systems to work together, hence the name “integrated.” ...
