The weather outside is frightful, inside it’s so delightful… it’s awfully early in the year to sing this song, but it’s what came to mind as I was researching this story on a particular hazard of summertime weather — lightning. It’s far more “frightful” than snow or ice — lightning can kill you instantly. (It can literally fry your heart and brain.) We’re now smack in the middle of lightning season (because of all the thunderstorms), and while some of us may be up on the latest information on what to do when lightning strikes, it’s remarkable how many people simply forget. I decided to seek out the latest information on staying safe.

A Bolt from the Blue?

In the summer months, lightning is predictably unpredictable — there’s lots of it and you don’t always see it coming. You’ve heard the term “a bolt from the blue”… it derives from the fact that lightning has been known to light up a bright blue sky (though not so often as a dark and stormy one) and it can travel as far as 10 miles, not only vertically but horizontally as well. Hot summer weather raises the likelihood of thunderstorms, which always bring lightning (whether you see it or not).

According to the National Weather Service, lightning strikes ground some 25 million times a year here in the US, hitting an estimated 400 people and killing about 40, who typically die from severe burns, cardiac arrest and/or respiratory arrest. While 90% of those who have been hit by lightning survive, they often suffer serious side effects that can include paralysis, internal and external burns, deafness, ringing in ears, amnesia and/or confusion, personality change, depression, sleep disturbances, memory dysfunction, headache, fatigue, joint stiffness and muscle spasms.

To learn how to stay safe and what to do if you’re ever with someone struck by lightning, I consulted our contributing medical editor Richard O’Brien, MD, an emergency physician in Scranton, Pennsylvania, who told me he sees lightning victims every summer.

While everyone seems to understand that lightning is dangerous, many are unclear on what they need to do to protect themselves. So, one by one, we went through the facts that are most important to know…

Are You Grounded?

The most important thing to understand about lightning, said Dr. O’Brien, is that it wants to find a way to get into the earth — it’s called “grounding.” The human body, water and metal all are excellent conductors of electricity and will get it to ground very effectively. Rubber, concrete and wood, on the other hand, are protective.

“When thunder roars, go indoors.” This is the catchy phrase that the National Weather Service uses to educate people on the most important thing you can do to stay safe from lightning — get out of its way. Get inside a safe building (one that is fully enclosed with a roof, walls, electricity and plumbing) or seek shelter in a car with a metal roof and the windows up (not a convertible, even with the roof up.) “There is no such thing as being safe outdoors in a thunderstorm,” said Dr. O’Brien. Even if you are inside, remember that lightning has been known to strike through glass. Stay as far away as possible from windows and skylights. Lightning also has been known to strike through electrical outlets. If it hits an outside wire (phone/cable/electric), it can conduct into the jacks in the house, Dr. O’Brien explains.

Stay dry and disconnected. You can use a cell or cordless phone safely during a thunderstorm as long as it’s not attached to the base. (Please note that you still risk drawing an electrical surge to the base and destroying it.) Do not talk on a landline. And there is no such thing as safe phone use