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A Striking Change in Lightning Deaths

By: Bob Henson 5:21 PM GMT on January 22, 2015

Already, the 21st century has brought us the deadliest U.S. hurricane since 1928 (Katrina, 2005) and the deadliest tornado since 1947 (Joplin, 2011). Here's much better news: the death toll from lightning has plummeted across the nation in recent decades, and the progress is holding up nicely. Veteran lightning analyst Ron Holle presented an update on national and global casualty trends at the American Meteorological Society's annual meeting in Phoenix earlier this month.

Figure 1. Cloud-to-ground lightning emanates from a summer storm in Albuquerque, New Mexico, on July 15, 2014. Image credit: wunderphotographer Don Armstrong.

A century ago, lightning killed more than 400 people in the United States each year, at a time when the nation's population was much lower. Back then, most Americans lived on acreages or in small towns, and lightning tended to strike people while they were working on the farm or ranch. Today, the U.S. death toll averages less than 30 per year. Unlike most other severe weather threats, lightning tends to kill people one by one, so there haven't been any mega-disasters to interrupt the long-term improvement. The progress is even more dramatic when looking at the death toll per million (see Figure 2, below).

Figure 2. U.S. lightning deaths per million people (red line) and the percentage of the population classified as rural (blue line). Image credit: Ron Holle, updated from López and Holle 1998.

What's behind the improvement? Holle cites a variety of factors, including the availability of lightning-safe buildings and metal-topped, fully-enclosed vehicles (i.e., cars and trucks) as ready sources of shelter. He also stresses the importance of NOAA's lightning safety initiatives, which have ramped up greatly over the last 15 years. The mantra "when thunder roars, go indoors" is widely known, and people are now urged to stay inside until at least 30 minutes have passed since the last clap of thunder.

When Americans do die from lightning, it's more likely they're boating on the lake instead of plowing the south forty. According to a statistical breakdown featured on the National Weather Service’s Lightning Safety website, leisure activities accounted for 64% of the 261 U.S. lightning deaths reported from 2006 to 2013. Routine daily or weekly chores, such as taking care of yard work or tending to farm animals, account for only 16% of deaths. Among leisure activities, the largest single category is "water-related," with nearly half of those deaths associated with fishing. The University of Florida has an extensive website on lightning’s hazard to sailboats. Being a sports fan also has its hazards: last month, seven people were taken to the hospital with minor injuries after a strike hit a car parked at Tampa Bay’s Raymond James Stadium following a Tampa Bay-Green Bay football game.

Lightning kills far more people in other countries
Data on lightning deaths around the world are hard to come by, said Holle, but the most recent analysis suggests that as many as 24,000 people around the world are killed by lightning in a typical year. The highest per-capita fatality rates are in southern Africa, whereas the largest national toll by far is in India, still a highly agricultural society with more than 1.2 billion residents. A typical year sees about 1,700 Indians killed by lightning.

U.S. society is affected more by lightning than our improving death toll might suggest. It's been estimated that for every person killed, roughly ten people are injured, often with life-changing consequences. And the proliferation of home electronics and gizmos means that a typical home lightning strike wreaks more havoc than it used to. According to Holle, the average U.S. insurance claim from a home strike was around $900 in the late 1990s, but more than $5000 in 2013. Structural fires caused by lightning inflict about half a billion in U.S. damage each year, according to the National Fire Protection Association. Throw in the additional expense from lightning-damaged utility systems, plus the average $1.8 billion in costs related to fighting wildfires triggered by lightning, and the broad economic toll of lightning becomes evident. (I’ve seen this on a personal scale, having lost a home computer to a lightning strike several years ago—thanks in part to an inadequate surge protector.)

Along with the increased damage that a single lightning strike can inflict on our highly wired society, lightning itself could become more frequent in coming decades. New research covered by Jeff Masters last autumn suggests the potential for 50% more lightning by the end of this century in a business-as-usual emissions scenario.

A manuscript expanding on Holle’s talk can be downloaded from the abstract web page. Video presentations will be linked to abstracts in February.

Bob Henson

Figure 3. Lightning prowls the cityscape of Tucson, Arizona, near sunset on August 13, 2012. Photo credit: wunderphotographer ChandlerMike.

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