Image: Courtesy NOAA
We may not know when lightning is going to strike, but scientists now have a much better picture of where it has struck in the past. NASA researchers recently announced that they have compiled the best map yet of historical lightning strikes. "For the first time, we've been able to map the global distribution of lightning, noting its variation as a function of latitude, longitude and time of year," Hugh Christian, leader of the National Space Science and Technology Center's lightning team says.

Previous attempts to generate global lightning maps relied on ground detectors. These monitors provided detailed local measurements but due to their limited range, oceans and low-population areas were poorly represented. To compile the new map, the scientists used two satellite-based detectors capable of picking up on brief lightning flashes even during daylight. Using high-speed cameras to analyze a narrow wavelength band in the near-infrared region, the sensors search for changes in the tops of clouds, which indicate lightning strikes.

The new map shows that Florida experiences an unusually high rate of lightning strikes. According to atmospheric scientist Dennis Boccippio, this quirk may result from the fact that Florida experiences two sea breezes that can interact to force ground air upwards and trigger thunderstorms. Lightning also shows an affinity for the Himalayas, where mountains cause the convergence of air masses from the Indian Ocean and central Africa, which experiences thunderstorms year round. If you want to avoid lighting, your best bets are oceanic regions such as Antarctica and the Arctic or¿if you prefer balmier climes¿islands in the Pacific.