A lightning prediction system is a type of lightning detection equipment that determines when atmospheric conditions likely to produce lightning strikes and sounds an alarm, warning those nearby that lightning is imminent and giving them the chance to find safety before the storm arrives in the area. Lightning protection systems are often installed in outdoor areas which are often congested with people, lack sufficient shelter, and are difficult to evacuate quickly (such as water parks, college campuses, and large swimming pool or athletic field complexes). These locations are particularly dangerous during lightning storms. Prediction systems are prone to false alarms as they respond to conditions that are not always attributed to a developing thunderstorm. Electric field data is typically used in conjunction with detection information to limit false positives.