Thor Guard
The Downers Grove Park District uses the Thor Guard Lightning Prediction System throughout the park network. The system predicts lightning strikes by measuring electrostatic charges on the ground and in the air.
The Thor Guard Lightning Prediction System is installed in four zones throughout the Park District. Each zone has a lightning sensor that sets off remote warning horns when lightning is imminent. The lightning prediction sensor at each of the four zones is independent of the others. Lightning sensors and remote warning horns are located at Lyman Woods, the Downers Grove Golf Course, Lincoln Center and McCollum Park. The system covers a total of 19 sites selected due to high recreation or sport use.
When the system predicts lightning in the area, a 8-second warning horn will sound. Depending upon weather conditions the warning horn may be heard within a two-block radius. Anyone who hears the horn should seek shelter immediately in a building or a hard-top vehicle. All activities at the parks should also stop when the horn sounds. Anytime lightning is visible, the best course of action is to seek shelter immediately.
After the danger is reduced, an all-clear signal of two short horn blasts (three horn blasts at the Golf Course) will sound. A strobe light will also flash until the danger has passed. The system is activated daily March through November.
Lightning Safety Tips 
The lightning sensors and warning horns are at the following locations:
| Lightning Sensor Park Locations | Lyman Woods | Golf Course | Lincoln Center | McCollum |
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For more information about the Thor Guard Lightning Prediction System call Director of Parks Todd Reese at (630) 963-1304.
