According to a study by the American Meteorological Society, the most intense thunderstorms in the world occur in the southern part of Brazil and northern Argentina in South America. The study was performed by NASA's Tropical Rainfall Measuring Mission satellite. Of the storms that occur in South America, Dan Cecil of the University of Alabama had this to say, "There's probably large hail coming from these storms, golf ball maybe even softball size hail, in these storms in Argentina and certainly very heavy rainfall, we are measuring the lighting --- the highest flash rate we've seen would be for a system that stretched the entire length of the nation of Paraguay and it was producing 1400 flashes every minute."
The article can be found here:
http://www.theworld.org/?q=node/5396&answer=true
