Advertisement

SKIP ADVERTISEMENT

Tech Tip

How Those Wireless Emergency Alerts Find You

Q. When I get an emergency alert on my phone for a certain area, how does the system know I’m in that location? Do these messages count against my monthly limit?

A. The Wireless Emergency Alerts system, which allows government authorities — like local law enforcement or the Federal Emergency Management Agency — to push out public safety warnings to mobile devices, can be restricted to certain geographic locations. Once officials have decided the range of the emergency zone, the alert is broadcast from the cell towers in that designated area.

Image
Emergency alerts from government and public-safety officials do not count toward your text message allowance.Credit...The New York Times

According to the Federal Communications Commission, participating wireless carriers are “generally required to send the alerts to a geographic area no larger than the county or counties affected by the emergency situation.” The agency also notes that carriers may be able to pinpoint smaller areas to receive alerts.

Targeting the alerts to precise geographic areas means that people in Indianapolis do not get flood warnings meant for residents of the Gulf Coast, or even those for nearby Kentucky. If you are visiting a place that is in an emergency situation, your phone should get the alert messages even though you don’t live there.

About 100 wireless carriers around the country participate voluntarily in the W.E.A. system, including the major national companies AT&T, Sprint, T-Mobile and Verizon Wireless. Prepaid phones can also receive the alerts, as long as the carrier participates in the W.E.A. program and the device is capable of getting the message. Carriers that do not participate in the program are required by the F.C.C. to notify their customers.

The emergency alerts are free and usually enabled on a phone by default, and they do not count against any text-message limits in your monthly data plan. Although the alerts resemble Short Message Service (SMS) communications, they are not standard text messages and are delivered using a different technology.

Personal Tech invites questions about computer-based technology to techtip@nytimes.com. This column will answer questions of general interest, but letters cannot be answered individually.

Advertisement

SKIP ADVERTISEMENT