Regardless of their severity, all thunderstorms are dangerous. Every thunderstorm produces lightning, which kills more people each year than tornadoes. Strong winds, hail, flooding, and tornadoes are other dangers associated with thunderstorms.
A typical thunderstorm is 15 miles in diameter and lasts an average of 20 to 30 minutes. Of the 100,000 thunderstorms that occur every year in the United States, only about 10 percent are classified as "severe."
NYC Lightning Facts
According to the National Weather Service, the Empire State Building is hit by lightning an average of 25 times per year. In one storm, it was hit eight times in 24 minutes.
New York State is considered to have a "moderate" occurrence of lightning, with 3.8 strikes occurring per square mile each year. This compares to 20 per square mile in Florida, and two in California.
While lightning can be fascinating to watch, it is also extremely dangerous. Lightning causes an average of 67 fatalities and 300 injuries each year.
The safest place to be during a thunderstorm is indoors. Postpone outdoor activities if thunderstorms are imminent.
Remember the 30/30 Rule. If you see lightning, count the seconds before you hear thunder. If it's less than 30 seconds, take cover. Once indoors, wait 30 minutes after the last clap of thunder before venturing back out.
Know the Terms
Severe Thunderstorm Watch: conditions are favorable for the development of severe thunderstorms in and close to the watch area.
Severe Thunderstorm Warning: Issued when a thunderstorm produces hail 3/4 of an inch or larger in diameter and/or winds which equal or exceed 58 mph.
Know What to Do
Downbursts and winds associated with severe thunderstorms can produce 100-150 mph winds. The resulting damage can equal that of most tornadoes. If a severe thunderstorm warning is issued:
Take shelter. Remember, indoors means indoors. Structures like bus shelters or any small non-metal structures do not provide sufficient lightning protection.
Pay attention to local weather forecasts and bulletins issued by the National Weather Service on local radio stations.
Shutter windows securely and brace outside doors.
Secure outdoor objects such as lawn furniture or garbage cans that could blow away and cause damage or injury.
In extreme conditions, consider shutting off power and appliance gas switches to prevent damage to your appliances.
Do not use the telephone or any electrical appliance connected to the building's electrical wiring.
Do not use showers, sinks, or any object, machine, or device connected to the building's plumbing system. If lightning strikes the building, the current will likely flow through either the electrical wiring or the water pipes, and you could receive a fatal shock.
Automobiles can also protect you from a lightning strike because the current will flow through the car's metal frame. If you are in a car, do not touch any exposed metal connected to the car.
If you are caught outside during a thunderstorm:
Try to get indoors. You are NOT safe outside. Also, crouching doesn't make you any safer outdoors.
Stay away from tall, isolated trees or other tall objects, and avoid large open areas like fields or parking lots where you are the highest object.
Stay away from water, wet items, such as ropes, and metal objects, such as fences and poles, which could carry current from a distant lightning strike.
If lightning is about to strike you or something extremely close, you may experience a tingling feeling on your skin and/or your hair may stand on end. If this occurs, quickly assume the position described above. Even if you are caught outside in a thunderstorm, do not panic. You will likely find sufficient shelter.
Stay clear of downed power lines.
If someone is struck by lightning:
Call for help. Call 911 or your local ambulance service. Get medical attention as quickly as possible.
Give first aid. If the victim has stopped breathing, begin rescue breathing. If the heart has stopped beating, a trained person should give CPR. If the person has a pulse and is breathing, address any other injuries. For information on how to learn CPR, contact your local chapter of the American Red Cross.
Check for burns in two places. The injured person has received an electric shock and may be burned, both where they were struck and where the electricity left their body. Being struck by lightning can also cause nervous system damage, broken bones, and loss of hearing or eyesight. People struck by lightning carry no electrical charge that can shock other people. You can examine them without risk.
If you must drive a vehicle:
Turn on your lights.
Pull onto the shoulder of the road and stop, making sure you are away from trees or other tall objects that could fall on your vehicle. Stay in the car and turn on the hazard lights until the heavy rain subsides.
Listen to your car radio and be alert.
Avoid contact with metal or conducting surfaces outside the inside the vehicle. Lightning that strikes nearby can travel through wet ground to your car.
Avoid flooded roadways. The depth of water is not always obvious.
If you find yourself in a skid , remain calm, ease your foot off the gas pedal and steer in the direction you want the front of the car to go. If your vehicle has anti-lock brakes, brake firmly as you steer into the skid. If your vehicle does not have anti-lock brakes, avoid using your brakes.
To avoid hydroplaning — which occurs when the water in front of your tires builds up faster than your car's weight can push it out of the way — do not brake or turn suddenly. This could throw the vehicle into a skid. Ease your foot off the gas until the car slows and you can feel the road again.