Lightning strike density

As our society becomes more and more technology dependent, we are becoming more vulnerable to inclement weather. Utilities, telecommunication, agriculture and transportation are all adversely impacted by lightning. However, no good lightning climatology is available. Most presentations show the annual number of "thunderstorm days" observed at weather stations. In a 1984 study by D. MacGorman, M. Maier and W. Rust for the Nuclear Regulatory Commission, it was noted that thunderstorm day information is a poor indicator of lightning strike probability because it does not take into account the duration of lightning activity. Days having a few minutes of lightning activity are treated the same as days having long-lived storms. In an effort to compensate for this, MacGorman, Maier and Rust analyzed thunderstorm data from 450 14-hour aviation observing sites. Their chart of thunderstorm days (Fig. 1) agrees with other climatologies. (Note, no attempt was made in this chart to "adjust" data to account for effects of topography .)