How wireless emergency alerts work

If you live in or close to New York City, your cellphone likely made a strange sound at about 8 a.m. this morning. The noise accompanied a special notification about the identity of the chief suspect in this weekend's Chelsea bombing, 28-year-old Ahmad Khan Rahami, with advice to call 911 if he's spotted.

This is the wireless emergency alert (WEA) system in action. Rarely used, the system takes advantage of smartphone technology to push urgent alerts out to the public quickly. Considering smartphone penetration in the U.S. is about 80% of the population — and most users carry their phones or have them nearby at all times — the WEA system is arguably more effective at pushing alerts to the public than TV-based emergency broadcast system (EBS). Read more...