Because of severe injuries and death caused by convective (rising warm-air) storms, the National Weather Service has compiled accurate statistics on the incidence of reported lightning casualties in the United States. Interesting conclusions from this database include:
Florida has twice as many lightning-based casualties than any other U.S. state, with 468 fatalities reported in 53 years (8.8 per year). High air temperatures and frequency of convective storms drive these statistics, as do the popularity of outdoor recreational activity in the country’s southernmost state.
In New England and along the West Coast, the probability of lightning fatalities is low and seasonal. In Hawaii and Alaska, it is improbable. These reportings have been supplemented in recent years by data from new satellite-based meteorological sensors.
Each year in the U.S., there are roughly 25 million lightning strikes. Worldwide, there are more than 100 strikes per second. The majority of strikes occur over land where air rises from solar heating. Strikes are rare over the open ocean but more common in coastal areas where warm waters can induce atmospheric convection, like over land.
A few anecdotes: People in low-latitude U.S. coastal states are more likely to be killed by lightning than to win a major lottery. Furthermore, men enjoying the Florida outdoors at about 4 p.m. on a Sunday in July are tempting fate as that scenario is when the chances of being struck by lightning are optimized. (The good news is that man will most likely be the only person to die from that lighting strike.)
BoatUS has compiled statistics on lightning strikes of vessels (not persons) from insurance claims submitted by their members. While its database does not include all vessel strikes for the entire nation, its 2010 analysis of claims submitted between 2000-2005 provides interesting results:
Lightning damage to a vessel is often readily apparent from physical damage and/or inoperable electronics. However, there are cases when lightning-damaged wiring or electrical components did not present themselves for many years, then finally failed or shorted out when least expected or desired. Recommendations for lightning preparedness for boaters are provided in my Marinas Guidebook (see reference below).
Next month, I will provide information on additional lightning topics, such as how lightning is formed and how strike locations are determined, how far strikes can occur from a storm center, and how to sense an imminent, local strike.
Scott E. McDowell has a doctorate degree in ocean physics, is a licensed captain and author of Marinas: A Complete Guide, available at www.scottemcdowell.com. Comments are welcome at firstname.lastname@example.org.