According to the National Weather Service, more than 25 million cloud to ground lightning strikes occur in the United States each year. A lightning stroke can generate between 100 million and one billion volts of electricity! Each year an average of 73 people each year are killed, and more than 300 injured by lightning in the United States. This is why it is important to know what to do when lightning is close by. Here are some things to consider, from the National Weather Service.