Lightning is a bigger killer in the United States than hurricanes or tornadoes.
It takes an average of 67 lives each year, according to the National Weather Service, which adds that lightning deaths and injuries peak during summer, whith the combination of lightning flashes and outdoor summertime activities. Two-thirds of all lightning strikes in the U.S. occur in June, July and August.
Over the weekend, almost 30 members of a family attending an annual reunion in Sugarcreek, Pa., outside Pittsburgh, were knocked over like dominoes when lightning struck a tree under which they had sought shelter.
The most seriously injured was 12-year-old David Rogan, who was knocked unconscious and stopped breathing for a while. His cousin, a nurse, and paramedics were able to revive him with CPR. David is at the Children's Hospital of Pittsburgh in critical but stable condition.
Family member Tammy Coon, says, "There was a large ball of light, and at the same time a huge, huge explosion. People just went to the ground. Some were thrown out of chairs. Some were knocked backwards."
The Early Show co-anchor Hannah Storm points out that it was raining off and on in the area, but guests didn't appear to think they were in a serious storm, and they didn't even hear thunder.
Holle urges people to follow the "30-30 rule," which the National Weather Service says should be used "where visibilty is good and there is nothing obstructing your view of the thunderstorm. When you see lightning, count the time until you hear thunder. If that time is 30 seconds or less, the thunderstorm is within 6 miles of you and is dangerous. Seek shelter immediately. The threat of lightning continues for much longer period than most people realize. Wait at least 30 minutes after the last clap of thunder before leaving shelter. Don't be fooled by sunshine or blue sky. If it is cloudy or objects are obscuring your vision, get inside immediately. It is always safer to take precautions than to wait."
"Don't go outside too soon," Holle concurs. "About as many people are killed and injured by lightning after the maximum part of the storm is done compared to before the storm."
"There's really only two safe places from lightning," Holle continues. "One is inside of a substantial building like a house or a business. And the other one is a metal-topped vehicle. When you're inside of a building, you want to stay away from the wiring and the plumbing and the telephone, because they'll conduct electricity in from a strike to the building or to a power pole.
If you're stuck outside during a storm, Holle says, "There's only so much you can do. You generally really need to be inside. …Most of the time, such as in the case of (the Pennsylvania) picnic or when you have a ball game, there is a vehicle nearby, and there's a building. Just go to those places."
Click here for National Weather Service lightning safety tips.