Recent figures suggest that the US is heading for a record low figure for lightning casualties, with only 13 deaths so far this year. While severe thunderstorms may be increasing the number of deaths attributed to lightning in developed countries keeps falling. In the 1940s, lightning killed several hundred people each year in the US.
Better emergency medicine means more people survive a strike, but the drop is largely because of increased awareness of the hazard: people know to take cover when a storm threatens. This is aided by increasing numbers of lightning warning systems at golf courses – a prime site for casualties – as well as in parks and on sports grounds.
Some warning systems work by detecting the radio emissions from nearby lightning strikes. These are good for gathering meteorological data, but may be too late for those on the ground.
An alternative approach detects the build-up of static charge on the ground which precedes lightning. People often describe their hair standing on end minutes before lightning strikes; instruments can provide more timely warning.
The makers of one such system, Thor Guard, claim that a single electrostatic sensor can cover an area 10 miles across. Mounted at a high point where charge accumulates the sensor continuously measures the changing electrostatic field and identifies the pattern of charge associated with lightning, sounding air horns to alert people to take cover.
We cannot prevent lightning. But more awareness, and better warnings, should mean deaths and injuries will continue to decline.
