Joliet tornado sirens aligned with warning areas

Joliet is upgrading its tornado warning system to set off sirens only in areas where there is a threat.

Fire Chief Joe Formhals told the City Council last week that new software was being installed to automatically activate sirens only in areas falling within the polygon-shaped warning zones designated by the National Weather Service.

The new software replaces a system that triggers every siren in Joliet.

"If any portion of that polygon touched the city of Joliet, all the sirens went off," Formhals said.

The city later issued a news release stating the upgrades started Friday.

The old system setting off all 23 sirens "is problematic for a city Joliet's size and causes confusion among our residents who may disregard future severe weather warnings as irrelevant," the release stated.

The new software will monitor the National Weather Service's tornado warning polygons.

"As storms move through the city and additional tornado warning polygons are issued, additional warnings sirens will be sounded," the release stated.

The dispatch center also monitors weather conditions and can activate sirens manually.

The city also is cautioning residents not to rely solely on warning sirens to monitor severe weather.

"These are outdoor warning weather sirens," Formhals said. "They're not meant to warn you when you're in the house."

He said the sirens are meant to warn people who are driving or outdoors to move into a building for protection.