ALPENA — When two reportedly armed men went on the run in the predawn hours of April 27, Alpena County’s Smart911 system allowed officials to warn thousands of residents to stay on the lookout.

That public warning about the early-morning manhunt illustrated the benefits and limits of the Smart911 system, which allows residents to sign up to automatically share information with emergency officials when they call 911 and sign up to receive public safety alerts.

Despite any limitations, officials still urge residents to sign up by creating an account at smart911.com or downloading the mobile app. Every resident who receives an alert can alert a neighbor, friend, or family member and, like ripples in a pond, important public safety information can spread, said Mark Hall, the county’s emergency services coordinator and 911 director.

Emergency officials sent the April 27 alert after two men who allegedly broke into a home on the 400 block of South 2nd Avenue and held residents at gunpoint eventually got away from police by hopping a fence bordering Decorative Panels International.

The men apparently remain at large. Police have released no further information about the incident, but said they believe the public faces no further danger.

The morning of the alleged break-in and subsequent manhunt, emergency officials alerted about 5,500 residents through Smart911, Hall said. About 7,500 residents have signed up to receive alerts, but officials can target alerts to a specific geographic area.

Depending on how residents chose to receive alerts, they may have received a text or a phone call.

Texts work best, Hall said, because the system can write the entire message and residents can read it all at will.

Phone calls get trickier, Hall said.

Many residents now screen all phone calls, letting unknown numbers go directly to voicemail. The Smart911 system will leave a message, Hall said, but, depending on a residents’ voicemail system, part of the message may get cut off, as happened to some residents last week.

Plus, with fewer and fewer residents using landlines, the number of residents signed up to receive an alert has dwindled. Four years ago, about 12,000 people had signed up, Hall said.

Still, the 911 director encouraged residents to sign up.

“It is a good system that we will continue to evaluate,” Hall said.

Hall said the county is on year four of its five-year contract with Smart911 and he’ll look into whether other systems might allow alerts without requiring residents to sign up.

He said the county can access the emergency alert system used by state and federal authorities to send notifications to all smartphones without residents signing up, but only certain emergencies, such as tornadoes or other natural disasters, qualify for that system.