Two people were killed just outside the White House Thursday evening and two more were critically injured when they were struck by lightning as they stood beneath a grove of trees in Lafayette Park as a severe thunderstorm erupted.
Wisconsin residents Donna Mueller, 75, and James Mueller, 76, were treated by members of the U.S. Secret Service and U.S. Park Police, but were later pronounced dead. Two other victims, whose names have not been released, remain in critical condition.
“We are saddened by the tragic loss of life after the lightning strike in Lafayette Park. Our hearts are with the families who lost loved ones, and we are praying for those still fighting for their lives," White House press secretary Karine Jean-Pierre said in a statement on Friday.
Ahead of the lightning strike, the National Weather Service issued a severe thunderstorm warning for the Washington area between 6:30 p.m. and 7:15 p.m. The fatal strike came at 6:49 p.m.
Chris Vagasky, a lightning analyst for Vaisala, a company that conducts weather and environmental measurements and a member of the National Lightning Safety Council, described the event as a "6-stroke lightning flash," meaning six separate surges of electricity hit the same spot within half a second.
“When you think of cloud-to-ground lightning and you look out and you see lightning flickering, each of those flickers is a stroke that comes down," Vagasky told Yahoo News. "For negative cloud-to-ground flashes, which is what this was, there’s generally multiple strokes to a flash.”
On average, lightning kills 23 people in the United States each year, and more than 2,000 die globally each year after being hit by lightning. Thursday's deaths brought the number in the U.S. killed by lightning to 11 for 2022.
"Lightning strikes the United States about 25 million times a year. Although most lightning occurs in the summer, people can be struck at any time of year," the National Oceanic and Atmospheric Administration says on its website, and hundreds of people "are severely injured" here annually.
If a person is struck, "Immediate medical attention, including calling 911, starting CPR, and using an AED, may be critically important to keep the person alive until more advanced medical care arrives," NOAA said.
There are five different categories of lightning strikes that can prove fatal, according to NOAA: A direct strike, which most often occurs in an open area; a side flash, when lightning strikes a taller object and "a portion of the current jumps from taller object to the victim"; ground current, when lightning hits a nearby object and "travels outward from the strike in and along the ground surface"; conduction, when lightning travels along wires, plumbing, metal fences, water faucets and showers, etc.; and streamers, transient electrical charges that are triggered when a primary strike forms.
Vagasky said that it is hard to say with 100% certainty what kind of lightning strike killed the Muellers on Thursday.
“What we’ve heard is that the four victims were standing under a tree, which leads me to believe that it’s either a side flash or conduction," he said. "Conduction could be that they’re standing right up against the tree and the electricity travels from the tree into them. Side flash would mean that they weren’t leaning on the tree, but the electricity jumped from the tree to them.”
Vagasky stressed that every kind of lightning strike is dangerous.
“Probably having a direct strike through a person is going to be the worst that you can come up against, because the electricity is going directly into you. But any lightning strike is going to have negative consequences to the human body," he said. "Any time lightning comes into contact with the human body, you’re going to have impacts to the cardiovascular system, to the neurological system, and that’s what causes the lifelong injuries or the fatalities to people.”
The Centers for Disease Control and Prevention offers advice on its website on how to stay safe during lightning storms.
"Remember the phrase, 'When thunder roars, go indoors.' Find a safe, enclosed shelter when you hear thunder. Safe shelters include homes, offices, shopping centers, and hard-top vehicles with the windows rolled up," the CDC website states.
If safe shelter is not an option, the CDC recommends the following:
Immediately get off elevated areas such as hills, mountain ridges, or peaks.
Never lie flat on the ground. Crouch down in a ball-like position with your head tucked and hands over your ears so that you are down low with minimal contact with the ground.
Never shelter under an isolated tree. If you are in a forest, shelter near lower trees.
Never use a cliff or rocky overhang for shelter.
Immediately get out of and away from ponds, lakes, and other bodies of water.
Stay away from objects that conduct electricity (such as barbed wire fences, power lines, or windmills).
While agreeing that the main takeaway about staying safe during a lightning storm was to remember the "when thunder roars, go indoors" adage, Vagasky added another piece of advice.
“We always like to remind people that there is no safe place outside during a thunderstorm, and dry does not mean safe. People will try to go under a tree or under a picnic shelter or things like that to get out of the rain, but that doesn’t protect them from the lightning," he said. "To be safe from lightning, you need to be in a fully enclosed metal vehicle, because the electricity would travel through the vehicle, or in a substantial building, one that has plumbing and electrical running through the walls because if lightning were to strike that building, the electricity runs through the piping or the wiring in the ground and keeps it away from people.”