Two weeks ago, the US Commercial Mobile Service Alert Advisory Committee (CMSAAC), an FCC-chaired body of industry representatives from local, state, & federal govt., the wireless communications industry, and media broadcasters agreed-to, and released public guidelines for implementing the proposed Commercial Mobile Alert System (CMAS) - a system manifestation of the Warning, Alert and Response Network Act (WARN) Act , a 2006 piece of proposed legislation that never made it past Congress. Under the CMSAAC passed rules, wireless carriers must, at a minimum, transmit text-based messages to all subscribers for the following geographic events:

National Presidential Alerts - national emergency-related alerts delivered to the American public that would preempt any other pending alerts;
Imminent Local Threat Alerts - alerts with information on emergencies that may pose an imminent risk to people’s lives or well-being; and
Local Child Abduction Emergency/AMBER Alerts - alerts related to missing or endangered children due to an abduction or runaway situation.

To implement the alerts, the CMSAAC agreed upon a proposed protocol called CAP (Common Alerting Protocol) - an XML exchange format for universal messaging, which was recently indoctrinated to de facto status by OASIS. The CAP API describes a single input to activate multiple cellular and media warning systems simultaneously allowing messages to flow across disparate networks and systems. The Emergency Interoperability Consortium (EIC) now has a MOU with the U.S. Dept of Homeland Security to adopt CAP for all citizen emergency alerting purposes.