The US networks operate an alerting network called the 'Wireless Emergency Alerts', or WEA. It is designed to broadcast various kinds of alerts to mobile phones and pagers following the Warning, Alert, and Response Network (WARN, which is one of the most awesome names for this kind of service imaginable) Act, which was passed by Congress in 2006. The system is designed to send out three kinds of alerts: those issued by the President of the United States, those alerts involving imminent threats to safety of life and AMBER alerts. They're delivered by a priority service that puts them ahead of Internet, call and text services (which is useful where the network is congested). The four big US carriers have all signed up to the service and although customers can opt out of most messages, it's forbidden to block messages from the President of the United States. The system integrates with the National Weather Service and can advise users of extreme weather conditions including tornados, flash flooding, dust storms, extreme wind or thunderstorms.
In July 2013, the New York police woke up a large number of people at 0400 hours, by issuing an amber alert regarding a missing child. This was a difficult decision for the New York police to take, because when a child goes missing the consensus of opinion is that with each passing minute, the chances of recovering the child are reduced. On this morning in July, New Yorkers' cell 'phones advised them of a missing seven-month old boy who had been abducted by his mother. The issued alert did help in the recovery of the missing baby... but many New Yorkers were less than happy at being woken at 0400 hours by their 'phone! Fortunately, Android 5.0 Lollipop is like other versions of Android and gives users the ability to modify their device's emergency service alert system.
You can control your alert preferences in the device Settings. Then look for Wireless and Networks. In here, you'll see a range of alerts that you can subscribe to plus reminders and vibration preferences. And of course, you can disable all alerts apart from the Presidential alert if you don't want to be bothered and enjoy life's little surprises! Have you been woken in the small hours by the alert service? Have you found it useful, or did you disable the service a short time after receiving the message? Have you used the alert service to advise people around you or loved ones who might not have seen the alert? Let us know in the comments below.