Lightning strikes are more dangerous, but stay away from sharks too

Q. Which is a greater danger, a shark attack or a lightning strike?

Studies show that lightning is a far greater killer than sharks in the United States. From 1959 to 2008 nationwide, 1,930 people were killed by lightning, while only 25 died from shark attacks.

The International Shark Attack File, part of the Florida Museum of Natural History, compiles the best data about shark attacks. The Shark Attack File statistics show that the odds of getting killed by a shark attack are 1 in 264 million.

To decrease your already small chance of becoming a victim of a shark attack, marine experts say you should observe the following rules:

1. Always swim in a group. Sharks most often attack lone individuals. 

2. Don’t wander too far from shore. Doing so isolates you and places you away from assistance. 

3. Avoid the water at night, dawn, or dusk. Many sharks are most active at these times and are better able to find you than you are to see them. 

4. Don’t enter the water if bleeding. Sharks can smell and taste blood, and trace it back to its source. 

5. Don’t wear shiny jewelry. The reflected light looks like shining fish scales. 

6. Don’t go into waters containing sewage. Sewage attracts bait fishes, which in turn attract sharks. 

7. Avoid waters being fished and those with lots of bait fishes. Diving seabirds are good indicators of such activities. 

8. Don’t enter the water if sharks are present. Leave immediately if sharks are seen. 

9. Avoid an uneven tan and brightly colored clothing.

Sharks see contrast particularly well, so use extra caution when waters are cloudy. 

10. Don’t splash a lot. Also, keep pets out of the water. Erratic movements can attract sharks. 

11. Use care near sandbars or steep drop-offs. These are favorite hangouts for sharks. 

12. Don’t relax just because porpoises are nearby. Sightings of porpoises do not indicate the absence of sharks. Both often eat the same foods. 

13. Don’t try to touch a shark if you see one! 

14. If attacked by a shark, the general rule is “Do whatever it takes to get away!” Some people have successfully chosen to be aggressive, others passive. Some yelled underwater, others blew bubbles.

Lightning strike

In a lightning strike, more than 10 million volts can hit you. It is fatal in about 30 percent of cases.

Most survivors have significant complications. Half of people struck by lightning will suffer rupture of the tympanic membrane in the ear. Many go on to develop cataracts.

“Lightning presents a grave risk of death,” warns Shreni Zinzuwadia, MD, an emergency department physician at UMDNJ-The University Hospital, and instructor of surgery at the UMDNJ-New Jersey Medical School. “Cardiac or respiratory arrest may result from being hit by lightning.”

In addition to a direct hit, there are three additional types of strikes. A side strike happens when lightning jumps from its initial point of contact to the victim. A contact strike occurs when lightning hits an object the person is holding or wearing. The other type of strike - step potential - happens when a current traveling through the ground goes up your leg, travels through you and then goes down the other leg and back into the ground.

Prevention begins by seeking cover at the start of a storm.

“Lightning seems to be concentrated at the forefront of a storm,” said Zinzuwadia, “so there tends to be a greater risk of being hit by lightning at the beginning of a storm.”

According to the Federal Emergency Management Agency, individuals who hear thunder should go indoors. Stay indoors until 30 minutes have passed after you hear the last clap of thunder.

Once inside, FEMA advises that people avoid contact with corded phones and electrical equipment or cords; do not wash your hands, take a shower, wash dishes, or do laundry because plumbing and bathroom fixtures can conduct electricity; stay away from windows and doors; stay off porches; and do not lie on concrete floors or lean against concrete walls.

If you are outside during a storm, crouch down and try to touch as little of the ground as you can, Zinzuwadia suggests. “Even if you are hit by the current, the less contact there is between you and the ground, the less likely it is that all of your major organs will be hit,” she says. “It increases your chances of survival.