[matthew-s]

These are most likely CMAS (Commercial Mobile Alert System). Best thought of as an extension of ye olde broadcast emergency alerts you see on TV and Radio.

They are broadcast at the cell tower level. All phones on that given cell tower will get the alert (assuming of course you have a compatible phone. only newer ones are, and not all of them)

There are three types of alerts: Imminent Threat (nasty weather and such), Amber alerts, and Presidential alerts.

You can opt-out of the Imminent Threat and Amber alerts by fiddling with your phones settings (if you so choose).

Unlike here on PARF, you can't opt-out of the Presidential alerts.

CMAS is a great thing. In an emergency, the more ways to get news out, the more likely you are to be informed.