The Deerfield Park District has sent notice about the testing of its Thorguard Lightning Prediction system taking place on Tuesday, April 3.
If atmospheric conditions are right for lightning to develop, the Thorguard system's horns and lights will activate, indicating that individuals should seek shelter.
One long horn blast indicates that there is a strong risk of lightning, while three short horn blasts signal that the threat has passed.
For more information, contact the Deerfield Park District at 847.945.0650.