The lightning strike on popular Venice Beach in Los Angeles on Sunday afternoon that left one person dead and 13 injured came in the midst of a thunderstorm that was highly unusual for the region.
Such storms normally miss the Southern California coast, but an unusual high-pressure system pulled in a hot, moist mass of air from the Gulf of California, which led to the lightning.
Scott Miller, an inspector with the Los Angeles County Fire Department, told National Geographic that lightning strikes are "rare and hard to predict."
A man in his mid-20s died at a Los Angeles hospital after being treated for a strike that hit the water and the beach, according to the fire department. Thirteen people who were in or near the water were also treated for injuries, including seven adults and a teenager who were taken to area hospitals.
Bill Patzert, a climatologist with the NASA Jet Propulsion Laboratory, told the Los Angeles Times that lightning and thunderstorms are quite rare in the region.
"Coastal Southern California is virtually lightning proof," he said, adding, "because it's so unusual, people are not sensitized to the dangers."
Patzert put the odds of lightning striking a person in California at 1 in 7.5 million. Odds are much higher in Montana, about 1 in 250,000.
John Jensenius, a lightning safety specialist with the National Weather Service in Silver Spring, Maryland, explains that when lightning hits the ground, the current tends to travel along the surface of the Earth, where it can injure anyone nearby. The same thing happens in the water. (See "Unraveling the Mysterious Impacts of Lightning on the Human Body" and watch: Lightning 101.)
"People think that when someone is struck by lightning it was a direct hit from the sky, but actually most people are struck by ground current," says Jensenius.
"People need to plan ahead so they can get to a safe place before the threat becomes significant," says Jensenius. "If you hear thunder, you are within striking distance and need to get inside as soon as possible."
U.S. Record of Strikes
There have been 16 fatal lightning strikes in the United States this year, reports the National Weather Service. Six have been in Florida, two in Colorado, and one each in Arkansas, Georgia, Michigan, Mississippi, New Mexico, Texas, and Wisconsin, in addition to California.
Before this weekend, the most recent incident came on July 22, when a man walking along a beach in Fort Myers, Florida, was struck.
Other deaths have occurred while people were hiking, horseback riding, trimming hedges, roofing, closing car windows, and even picking blueberries.
"Any activity outside during a thunderstorm is dangerous and people need to get inside immediately," says Jensenius. (See "Fishing and Camping Top Activity List for Lightning Deaths.")
Over time, lightning deaths have declined in the U.S. to a record low of 23 last year. The 10-year average is 33, while the 30-year average is 51. Jensenius credits greater awareness and preparation.
Lightning strikes remain significantly higher in a number of developing countries, such as India and Malaysia, where people often lack access to secure shelters and are often working outdoors.
Lightning Safety Tips
Miller says Los Angeles beaches don't have official guidelines on where people should seek shelter during storms.
"After they hear thunder, our lifeguards try to get people out of the water within the first 30 seconds, but that's a really difficult task when confronted with many beachgoers," he says.
Jensenius says people should seek shelter at the first sign of thunder. Sturdy buildings are best, since tents and temporary shelters provide little protection. If no buildings are available, hardtop vehicles are second best. (See photos of lightning.)
Always avoid being the tallest object around and avoid lying on the ground, since current tends to travel across it.
When indoors, stay away from items that could conduct electricity, such as wires, corded phones, plumbing (sinks, showers, and so on), and windows and doors, which often have metal parts that can conduct electricity inside, he says.
Wait 30 minutes after the last thunderclap or bolt of lightning before returning outside. (See more lightning safety tips.)