LTIFLASH is a program that is based on the electrogeometric model of lightning and takes a Monte Carlo type statistical approach to determining the places where lighning might strike. Briefly, the system under study is outlined by a series of masts, wires and quadrilateral planes, each of these being idenitified by the x, y, z coordinates of the start and end points. Some masts and wires may represent elements of a lightning protection system that is designed to intercept lightning while others might represent portions of a system that are supposed to be protected against being struck by lightning or to outline a region where one wants to keep track of the number of lightning flashes that might strike.