THOR GUARD L150 The THOR GUARD L150 Lightning Prediction System scientifically predicts the probability of a lightning strike, including the very first strike, within a defined area of approximately five miles in diameter. THOR GUARD is designed to provide adequate warning, so customers may safely find appropriate shelter prior to a lightning strike. More than 30 years, representing many thousands of hours of research and observation of storm activity have been invested in our proprietary algorithms. The culmination of these ongoing efforts enable THOR GUARD to monitor and evaluate the changes and intensity of electrostatic energy associated with lighting activity, a proven and superior approach to a typical detection system.