Minutes before a deluge of rain and hail hit the south Decatur neighborhood of Oakhurst on Saturday, a siren sounded a steady wail.

A man's voice boomed: "Attention. A tornado warning is in effect for Agnes Scott College. Seek shelter now. I repeat: A tornado warning is in effect."

Jemal R. Brinson/AJC (ENLARGE)

State emergency officials do not track which agencies have outdoor warning sirens for dangers such as tornadoes. This map show the location and number of most sirens in the metro Atlanta area.

Hyosub Shin/Staff Photographer (ENLARGE)

Henry Hope, director of public safety, stands near the siren (right) at Agnes Scott College. Such weather warning systems are not evenly spread out in the area.

STORM AFTERMATH • IRS giving storm victims more time to file • Officials believe man killed in tornado was seeking shelter • Federal aid available in Fulton PHOTOS: • One month after tornado • Oakland Cemetery • NW Georgia devastation • Scene downtown 3 days after • East Atlanta recovers • Cabbagetown • Vine City | Rome • Aerial view of damage • Downtown 1 | 2 • Readers' photos 1 | 2 | 3 MORE: • Woman killed by tornado mourned • Landmarks damaged | Map VIDEOS: • On YouTube • Aerials show downtown devastation • Atlantans survey damage • Storm hits MORE ALERTS: • Get AJC breaking news & traffic alerts on your mobile device.

Perched atop a college library, the siren didn't reach only students. It also delivered the primary warning for residents nearby who were not tuned in to a television, radio or the Internet.

Agnes Scott's siren is a rare piece of equipment in DeKalb County, which dismantled its outdoor siren system years ago. Fulton County did the same, citing upkeep costs.

As a result, no such alert sounded in Atlanta or unincorporated Fulton before the tornado struck downtown Friday night. Only residents within earshot of a city or school that had bought its own sirens heard them.

Outdoor sirens can now broadcast detailed voice messages over expansive areas, but their use remains scattershot across the metro area, The Atlanta Journal-Constitution found.

State emergency officials do not track who sounds what sirens or where. State authorities play no role in deciding when to set them off or what a so-called "big voice" should say.

That leaves counties and cities on their own to navigate debates about cost, usefulness and appropriate warnings.

"We do not have a position one way or another," said Buzz Weiss, a spokesman for the Georgia Emergency Management Agency. "We feel that is a local decision."

Last weekend's tornadoes were only the most recent to hit the area. Severe tornado-producing storms in 1998 prompted cities such as Duluth to get grants and build new siren networks.

Yet a decade later, some of the most populous neighborhoods in the metro area remain dead zones for such audible alarms.

Atlanta resident Thomas House said he was stunned to learn a tornado had crashed into Cabbagetown minutes after he and friends left a restaurant there Friday night. A siren could have warned them, he said.

"You could imagine an outdoor event, such as a major event at Piedmont Park or downtown in Centennial Park, and a tornado coming toward them and people not knowing," said House, who is 39 and works for Polo Ralph Lauren Corp.

The city should invest in sirens, he said.

Atlanta City Councilman Jim Maddox said this week that residents have called him about the city's lack of an outdoor alert system.

"Is there anything in the works to reactivate something like that?" Maddox asked city officials at a meeting. "Because a lot of people perhaps may not be looking at television, may not be listening to the radio."

In Fulton, cities from Alpharetta and Roswell on the north side to Union City and College Park on the south side have sirens — but the county itself doesn't.

In the wake of last weekend's storms, the Atlanta-Fulton County Emergency Management Agency will look more closely at whether sirens are needed, Director Rocky Moore said this week.

"Obviously, we recognize there are some opportunities to be considered for outdoor emergency warnings for open park areas," Moore said.

But for now, he said, his agency encourages residents and businesses to buy all-hazard weather radios, which provide more specific information than sirens.

Fulton County emergency officials recommended installing an early-warning siren system after the 1998 storms. The county never did. A network of sirens costs hundreds of thousands of dollars and requires testing and maintenance. Sometimes, they are hard to hear in cars or buildings.

"There are some folks who want them and some folks who don't think they're necessary," Moore said.

Ron Trumbla, spokesman for the National Weather Service's southern region, said he does not know of any states that require communities to use sirens.

"We see the sirens as a good outdoor warning system," he said. "We see the NOAA weather radios as the ideal indoor warning system."

Yet even as Fulton and DeKalb took a pass on outdoor alert systems, other cities and counties in the metro area embraced them.

Cobb County and the city of Smyrna, for instance, have erected a 90-siren network that includes about 15 sirens that were acquired from Fulton's and DeKalb's dismantled systems, said Lanita Lloyd, deputy director of Cobb's Emergency Management Agency.

The sirens are placed in areas where large groups of people gather outdoors regularly, such as high schools, she said. Authorities set them off when the National Weather Service issues a severe thunderstorm warning with a tornado watch, or a tornado warning, or if a trained storm spotter has reported a twister.

Duluth police Maj. Don Woodruff remembers how the early-morning tornadoes took the city by surprise in 1998. Sirens could have roused people and prompted them to take shelter, he said.

"There are darn few people up in the middle of the night watching TV," Woodruff said. "If it saves one person's life, it's worth the money."

Emory University installed seven sirens on its Clifton Road campus last fall, emergency preparedness director Alex Isakov said.

Not every agency that wants the alarms has them. In June, Gwinnett County sought a $450,000 federal grant to buy 11 sirens, police Cpl. Illana Spellman wrote in an e-mail. Gwinnett, which had none, lost out to counties elsewhere that had suffered damage that year.

Staff writer Eric Stirgus contributed to this article.