Weather Whys; Lightning Rods

This is weather-wise. Ever since man began building structures above ground, lightning has posed a serious hazard. Nationwide, lightning causes millions of dollars' worth of damage each year. And that's with the benefit of modern protection equipment such as lightning rods. Before lightning rods were invented, lightning flashes destroyed countless buildings every year. But since the rods went into use during colonial times, many more structures have survived direct lightning strikes. The principle of lightning rods is fairly simple. The objective is not to prevent a lightning strike, but to provide a safe path for the strong electrical current to take from the point of the strike to the ground. An array of metal rods on top of a building all connected together by a good conductor and well grounded. Greatly increases the probability that the path taken by a lightning discharge will be through one of the rods and the ground wire, rather than some part of the building. The wire that's used to connect the rods to the ground needs to provide low enough resistance to an electrical current to prevent heat from building up and possibly starting a fire.

In fact, in most cases, it's desirable to have a lightning rod and grounding system that can withstand a number of strikes and remain intact. That means the wire must be of a large enough gauge that it won't melt or fuse, even if struck by the strongest of lightning discharges. Weather-wise is produced with the assistance of the National Weather Service Forecast Office and the National Severe Storms Laboratory, both in Norman, Oklahoma, and the Cooperative Institute for Mesoscale Meteorological Studies, the Oklahoma Climateological Survey, and the School of Meteorology, all at the University of Oklahoma. Weather-wise is made possible with a grant from the National Science Foundation. I'm Drew Barlow.