Lightning Prediction SystemsLightning Detection Systems Sunrise, Florida-based Thor Guard produces most of the lightning prediction or detection systems in the Lake Travis area. Financed by school bonds, Eanes ISD installed seven Thor Guard lightning prediction systems in the school district in 2007 at a cost of $84,621, and Lake Travis ISD installed three systems in its district between 2012 and 2013 at a cost of $45,000, EISD director of communications Claudia McWhorter and LTISD director of communications Marco Alvarado said. The city of Bee Cave’s system, installed June 1, was partially financed by a $10,000 donation. The city of Lakeway and the Lake Travis Youth Association also use lightning detection systems. that determine the presence of lightning, said Andra Dearing, Lakeway’s parks and recreation director. Thor Guard’s system is based on electrostatic readings, representative John Watson said. Every thunderstorm produces a unique electrical footprint, or electrostatic field, where lightning will most likely occur, he said. The system detects when the electrostatic field is approaching an area and samples the atmosphere 52 times per minute, he said. “Thor Guard measures the electrostatic buildup and changes in the atmosphere,” Watson said. “When [the electrostatic field] reaches a certain preset level of threat, the system is automatically activated.” He said the system, when activated, sounds an alarm and flashes lights.