Lightning: Watch out for those flashes in the sky

MPR meteorologist Bill Endersen writes:

While tornadoes get the most attention during severe weather, lightning has been in the news this past week following the burning of several homes and possibly other structures. Lightning also is an underrated hazard for people even during garden-variety thunderstorms.

In the above photo from Getty Images, lightning flashes over the nighttime sky of Las Vegas, Nev.

Historically, only floods cause more storm deaths than lightning in the United States. And, in an average year, lightning kills more people than tornadoes and hurricanes combined. But lightning deaths tend to occur singly and without the dramatic photos and videos that make the evening news from those other events.

Lightning is a big spark of static electricity generated by a thunderstorm. About ninety percent of lightning flashes remain in the clouds, but researchers estimate that the remaining ten percent amount to approximately 25 million cloud-to-ground strikes in the United States each year.

Most lightning victims are outdoors in open areas, including on lakes, when struck. Lightning tends to strike taller objects, although not always. But don't take shelter under one of the tallest trees around. If you are caught outdoors, take shelter beneath something low or crouch down with only your feet on the ground.

Lightning is just as likely to strike an insulating material, such as a tree, as a metal flagpole. So head indoors whenever thunderstorms approach. Many lightning casualties occur before the rain arrives as it is the rain that often drives people indoors. Demographically, men, especially younger men, are significantly more likely to be lightning victims than are women.

Once indoors, stay away from things connected to the outdoors, especially metal things such as land line telephones. It is safe to use cordless appliances such as cell phones and TV remotes.

Lightning can do odd things. It struck a tree in my sister's yard, traveled along the tree roots, jumped through the foundation, shot through the house electrical system and blew out many appliances.

Cars are relatively safe places during lightning as the charge usually will pass through the metal body on its way to the ground. The rubber tires do not provide any safety and may explode when the lightning passes through. Likewise, rubber-soled shoes do not provide any protection. If lightning can go down a tree it can go through your shoes.

A direct strike usually causes death due to cardiac arrest or stopped breathing. Fortunately, most lightning strikes are indirect, such as when lightning strikes a nearby tree and then sends current along the ground and through the victim. Immediate injuries can include burns, damage to internal organs and ruptured eardrums. Lightning victims carry no lingering charge so they can be given first aid safely. About ninety percent of lightning victims survive but many sustain life-long disabilities including neurological problems.

The National Weather Service has all sorts of lightning info at their site www.lightningsafety.noaa.gov.

And if you just can't get enough lightning around here, head for central Florida or the Front Range of the Colorado Rockies on a July afternoon.

Bill Endersen