Some states are using emergency phone alerts to send virus information.

It was the day before Thanksgiving when Brian Stone, of Tilghman, Md., heard the alarm ring from his phone: the jarring buzz that tells people to look out for missing children or evacuate their homes to escape an advancing wildfire.

But this alert was different: It told him to wear a face mask and to expect stricter enforcement of coronavirus health orders.

Mr. Stone then turned off the notification system.

“You get this beep, this electronic sound, and you think it’s something important, and it’s just ‘Wear a mask and be safe,’” said Mr. Stone, whose wife, Ellen, wrote a letter to The Baltimore Sun about the emergency alert. “It wasn’t an emergency.”

Ed McDonough, a spokesman for the Maryland Emergency Management Agency, said: “We’ve been trying to be very judicious in how we use it.” Mr. McDonough said officials felt that with families gathering for Thanksgiving, it was important to remind them to be as safe as possible.

State and local officials are turning to the Wireless Emergency Alert system to warn residents of rising case counts and of other public health issues related to the virus. The model allows police departments and other public agencies to warn residents with geographically targeted messages, usually when there is severe weather or a child has been abducted.

In Los Angeles, officials used the system to tell residents that virus testing sites were expanding their hours ahead of the holidays.

On Monday, Rhode Island issued an alert to warn residents that hospitals were at capacity. And in Pennsylvania, Gov. Tom Wolf said in a news release last week that the state would use the alerts to target specific regions of the state with high case counts.

While emergency alerts provide an easy way to get important information to residents, the system also potentially oversaturates people with messages, creating a “boy who cried wolf” effect that could lead people, like Mr. Stone, to become disillusioned with the system.

Mr. Wolf said the alerts are “one more way to reach as many Pennsylvanians as we can to provide timely information on Covid-19.”