Take safety steps during most dangerous month for lightning strikes

Story highlights

  • National Weather Service: "When thunder roars, go indoors"
  • If no buildings are nearby, seek refuge in a metal-topped car with windows closed
  • 90% of lightning victims survive, but many have lifelong disabilities

(CNN)A group of hikers were 500 feet below the summit of a Colorado mountain in 2015 when storm clouds suddenly filled the sky.

A lightning strike -- a brief but intense burst of electricity -- affected as many as 16 hikers. Three were rushed to a local hospital and eight others required medical treatment, according to the Clear Creek County Sheriff's Office. All the hikers survived the incident, but one hiker's dog was killed.
Across the country in Greeleyville, South Carolina, lightning may have caused a fire at Mount Zion African Methodist Episcopal Church that gutted the interior and collapsed the roof, according to the FBI.
    July is the month when the number of lightning strikes -- and fatalities -- is at its highest. On average, 49 people are killed and hundreds more are injured in the United States each year by lightning strikes.
    The odds of being struck in your lifetime are about 1 in 12,000, the National Weather Service estimates. But experts say there are a few rules to help keep people safe.
    "We need to look at lightning safety proactively, not reactively," said Dr. Mary Ann Cooper, a physician and lightning researcher who directed the Lightning Injury Research Program at the University of Illinois at Chicago. "Avoiding situations where lightning can strike is key."

    One simple rule

    The National Weather Service recommends one rule to avoid lightning injuries: "When thunder roars, go indoors."
    No place outside is safe when there are thunderstorms in the area, they say, as lightning can strike 10 to 15 miles away from a storm. If there isn't a structure nearby, a metal-topped vehicle with closed windows can provide safety.

    Stay safe indoors

    Although the safest place from lightning is indoors, there a number of extra precautions to take once inside.
    A common misconception is that metal objects or water "attract" lightning. In reality, they're no more likely to be struck than a piece of cardboard or a person. The danger occurs because metal and water better conduct electricity once they're zapped.
    The National Weather Service recommends people avoid washing hands or taking a shower, and touching or even unplugging electrical devices plugged into walls, as these can conduct electricity from a lightning strike.

    Disregard outdated advice

    Experts said there's some truth in the idea that lightning is more likely to strike the tallest object in an area -- for example, a tree or a skyscaper -- and that "pointier" objects are more likely to be hit.
    But being outside at all during a thunderstorm puts you at risk of getting struck. The "lightning crouch," which was once thought to keep people safe during a lightning storm, is no longer recommended, Cooper said. There is no "safe" place outdoors during stormy weather.
    "Lightning doesn't know if you're 6 feet tall or 3 1/2 feet tall after it's traveled miles through the air," said Cooper, who is the founding director of the African Centre for Lightning and Electromagnetics.

    It's not always a direct hit

    It's a common misconception that a person needs to be struck directly to be injured by lightning, Cooper said. Only 3% to 5% of injuries are from direct strikes, she said.
    There are several ways lightning can reach a victim's body and cause injury. More than half of lightning-related injuries result from what's called a "ground strike," where lightning strikes the Earth and spreads through the ground, eventually reaching a person, Cooper said.
    "A lightning 'side flash' also kills a tremendous portion of people," Cooper said. "That's where lightning travels down a tree and sideways where a person might be standing."

    After lightning strikes

    The surge of electricity from a lightning strike can wreak havoc on a person's heart, brain and nervous system, and it can cause instant death by "short-circuiting" the heart. A survivor of a lightning strike might live with severe brain damage that can make activities such as memory, learning and task organization difficult.
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    "Ninety percent of people who are injured by lightning survive, but disabilities can last for a lifetime," Cooper said. "I've seen significant devastation to families from lightning injuries."
    If you witness someone struck by lightning, get emergency medical help right away. If multiple people are impacted, help anyone unconscious first. If the person has stopped breathing or has no pulse, correct CPR should be attempted immediately.
    "If the person is breathing, talking and making sense, there is no emergency and generally little a physician would find or be able to treat," Cooper said. Some symptoms may not be noticeable until later, when a person is unable to carry out daily responsibilities in the way they did before.
    "Many people who are struck by lightning describe it as a blunt force... like being impacted by an explosion," Cooper said. "Others may feel the sensation creeping up one leg, or as a burning or searing pain."