Combine the speed of lightning with the heat it creates and you have a sometimes deadly outcome.
About 90 percent of people struck by lightning survive but survivors often have lasting effects from the fraction of a second that the bolt hits.
Lightning can create temperatures around 50,000 degrees Fahrenheit which is five times the temperature of the sun's surface. So strikes often result in serious burns and lasting scars. The electric current is so powerful it can affect the electric rhythm of the heart when it hits someone. That can lead to cardiac arrest-- a frequent killer in these cases.
Doctor Richard Talbot at the Medical Center of Aurora's Saddle Rock ER has treated strike victims before.
"People who survive, the overwhelming majority of them seem to have delayed neurological consequences. Concentration difficulty, personality changes, difficulty multitasking," he said.
Dr. Talbot stressed the importance of being aware of the weather. He said call 9-1-1 right away if someone near you has been hit.
If you know CPR and the person is unconscious, start that procedure as soon as possible.