Summer Notice: Lightning Warning System
Oak Brook Park District’s Lightning Prediction System is in operation from April - November.
ONE PROLONGED BLAST OF THE HORN: Immediately seek shelter in a vehicle or building, conditions are right for generating lightning. ALL OUTDOOR ACTIVITY MUST CEASE.
THREE FIVE-SECOND BLASTS: All clear signal-risk of lightning has diminished. AVOID: Open areas, water, tall trees, metal fences, cellular phones, and radios.