Updated 07/05/11 – 6:34 p.m.

DOWNERS GROVE, Ill. (CBS) — Minutes count when a tornado is approaching, and that is where sirens can save lives.

As CBS 2′s Mike Puccinelli reports, officials in west suburban Downers Grove are making some changes to their tornado alert system, after a tornado struck the town last month – but the air raid sirens never went off.

The National Weather Service had issued a tornado warning at the time a twister blew through Downers Grove on the evening of June 21.

But Downers Grove required a funnel cloud actually to be spotted in order for the sirens to be activated.

April Prescott was sad she lost her tree to last month’s storm, but she’s glad the tornado that toppled it knocked it away from her house. It was lucky, because she and her children had received no warning about a tornado when the storm hit, because the village’s warning sirens never went off.

“It was shocking. You know, so it was really shocking and scary because we have two little boys so, you know, we would have taken the proper precautions because it was so quick,” Prescott said.

Her neighbor was also in harm’s way with her children when her tree was blown over.

“That’s actually horrible. We would have to be warned we needed to go to the basement or something. I was sleeping, I didn’t hear anything,” Seada Karajic said.

Village officials never activated the warning sirens because no funnel cloud was actually seen within five miles of the village.

“That was based on the criteria which requires a sighting,” Downers Grove Communications Director Douglas Kozlowski said. “We realize that that no longer meets the expectations of the community in terms of public safety and took immediate action to actually correct that.”

The new policy, put into effect on July 1, is similar to that of surrounding towns that did activate their sirens. Under the new policy, the sirens would be activated without a visible sighting of a tornado.

Sirens would be activated if a tornado warning has been issued for the area, or if top village officials determine there’s an imminent threat from a tornado or severe winds.

Village commissioners will review the new policy at a village board meeting on Tuesday.

On June 21, an EF-1 tornado hit Downers Grove at 8:31 p.m., and took a two-mile southwesterly path from approximately 55th and Main streets to Woodward Avenue near 71st Street. It touched down for about two minutes, and its maximum wind speed was about 90 to 100 mph. Its maximum width was 200 yards.

Right in the path of the tornado was Downers Grove South High School, at 1436 Norfolk St. near 63rd Street and Dunham Road. The campus of the high school sustained major damage – particularly the athletic fields.

A tornado also struck Mount Prospect that evening.