CLEARWATER — It was just after lunchtime Sunday when a summer storm rolled over Clearwater Beach.
Lifeguards raised two red flags on each stand at about 12:30 p.m., signaling dangerous weather, and whistled for swimmers to get out of the water, city officials said. A group of eight started to pack up and leave.
Then, just 12 minutes after the lifeguards' signal, the sky flashed.
A bolt of lightning struck the area. One man in his 40s suffered a direct strike and went into cardiac arrest. He remained in critical condition at Morton Plant Hospital as of Monday morning, hospital officials said.
Three others were taken to the same hospital. A fifth was taken to Tampa General Hospital to be treated for burns. The remaining three opted not to go to the hospital. Clearwater Fire & Rescue declined to release the names of those involved in the incident, citing medical privacy laws.
PREVIOUS COVERAGE: Eight injured in Clearwater Beach lightning strike
Lightning is a common and hair-raising sight during Florida summers. Here are some facts you may not know about the phenomenon.
1. Florida is considered the lightning capital of the U.S.
There are many metrics to determine how cities and states measure up against each other when it comes to lightning, and, like all weather, it changes from year to year. But there's no debate that Florida has the right ingredients for thunderstorms, particularly during the summer months, said Martin Uman, distinguished professor of electrical and computer engineering at the University of Florida.
The sea breezes from the Atlantic Ocean and Gulf of Mexico, plus the state's extreme heat and humidity, leads to a steady stream of hot air perfect for storm development.
"If you look at the radar in the afternoon there's almost always a line of storms just inland on both coasts, and then in the afternoon they work their way further land," Uman said. "We just have a more or less optimum situation."
PREVIOUS COVERAGE: Data disprove Tampa's lightning capital claim
One metric offered up by National Weather Service lightning safety expert Jeff Peters deals with lightning flashes. Texas had almost double Florida's number last year, but break it into flashes per square mile, and Florida sits at the top: about 21 per square mile annually compared to Texas' 11 per year between 2009 and 2018, according to data from Vaisala, a weather service contractor.
Florida also had the most fatalities over that period with 49 deaths. Texas was next with 20.
But while Florida stands out in the U.S., Uman said there are areas outside the country with far more lightning production.
2. Men are killed by lightning strikes far more often than women are.
Take 2017 as an example: only one woman was among the 16 people killed by lightning that year, according to weather service data. In 2018, four out of 20 victims were women. So far this year, two out of the eight fatalities were women.
It comes down to the outdoor activities and jobs that men generally participate in more often, Peters said, such as roofing and construction to fishing and golfing.
Generally, strikes are survivable — if you can get help quickly, said Matthew Pasek, an associate professor of geoscience at the University of South Florida.
"When you're far enough from medical care," Pasek said, "you may not survive."
In the Clearwater Beach case, a bystander performed CPR on the man who suffered a direct hit until first responders arrived, officials said.
3. Lightning affects nature.
It is a leading cause of forest fires and one of the few causes in remote areas. Just last month, a lightning strike sparked a 17,000-acre wildfire in the Everglades a mile north of Interstate 75.
But it also has a more subtle impact on foliage, Uman said. Florida's mix of pine and oak trees is in part due to storms. Lightning strikes the taller pine trees, letting sunshine through for shorter oak trees to grow and thrive. Some seedlings can also sprout out of the ash of a forest fire.
"The ecology of lightning — it turns out to be fairly important for the world's forests," Uman said.
4. How powerful was a lightning strike? Check the rocks.
When lightning hits sand, it forms a tube of glass called a fulgurite, said Pasek.
He uses fulgurites to interpret the size, speed, temperature and energy level of a lightning strike. Sometimes the results are staggering, he said. He's seen evidence of a lightning strike hitting the ground with the same impact as a semi-trailer truck.
"If lightning can vaporize rock," he said, "imagine what it can do to a person."
5. Is it safe to be in your bathtub during a storm? Not really.
The safest place you can be during a storm is indoors, but there are still risks. Touching metal appliances or plumbing fixtures with wiring or pipes connected outside is risky because lightning can travel through them, Uman said, though that's rare.
Same thing with a car. It's the metal body, not the rubber tires, that protects by conducting an electrical charge into the ground.
"Lightning can do anything. It can strike you even if you're inside your house," Pasek said. "But you're a lot more safe inside your house than you are outside."
Staff writer Sam Ogozalek contributed to this report. Contact Kathryn Varn at (727) 893-8913 or email@example.com. Follow @kathrynvarn.