THUNDERSTORMS and LIGHTNING Some Thunderstorms Can Be Seen Approaching, While Others Hit Without Warning

F A C T S H E E T

THUNDERSTORMS AND LIGHTNING Some thunderstorms can be seen approaching, while others hit without warning. It is important to learn and recognize the danger signs and to plan ahead.

Learn the thunderstorm danger Severe Thunderstorm Learn how to respond to a signs. Watches and Warnings tornado and flash flood. ¥ Dark, towering or threatening Tornadoes are spawned by clouds A severe thunderstorm watch is issued thunderstorms and flash flooding ¥ Distant lightning and thunder by the National Weather Service when can occur with thunderstorms. the weather conditions are such that a When a “severe thunderstorm Have disaster supplies on hand. severe thunderstorm (damaging winds warning” is issued, review what ¥ Flashlight and extra batteries 58 miles per hour or more, or hail actions to take under a “tornado ¥ Portable, battery-operated radio three-fourths of an inch in diameter or warning” or a “flash flood and extra batteries greater) is likely to develop. This is the warning.” ¥ Emergency food and water time to locate a safe place in the home Develop an emergency and tell family members to watch the ¥ Nonelectric can opener communication plan. sky and listen to the radio or television In case family members are ¥ First aid kit and manual for more information. separated from one another ¥ Essential medicines A severe thunderstorm warning is during a thunderstorm (a real ¥ Cash and credit cards issued when a severe thunderstorm has possibility during the day when ¥ Sturdy shoes been sighted or indicated by weather adults are at work and children radar. At this point, the danger is very are at school), have a plan for Check for hazards in the yard. serious and everyone should go to a getting back together. Dead or rotting trees and branches safe place, turn on a battery-operated can fall during a severe thunder- radio or television, and wait for the “all Ask an out-of-state relative or storm and cause injury or damage. clear” by the authorities. friend to serve as the “family contact.” After a disaster, it’s Make sure that all family members often easier to call long distance. know how to respond after a Make sure everyone in the family thunderstorm. knows the name, address, and Teach family members how and phone number of the contact when to turn off gas, electricity person. and water. Contact your local emergency Teach children how and when to management office or American call 9-1-1, police, fire department Red Cross chapter for more and which radio station to tune to information on thunderstorms for emergency information. and lightning. If indoors: ■ If you are isolated in a level Check for injuries. ■ Secure outdoor objects such field or prairie and you feel your A person who has been struck as lawn furniture that could blow hair stand on end (which indicates by lightning does not carry an away or cause damage or injury. that lightning is about to strike), electrical charge that can shock Take light objects inside. drop to your knees and bend other people. If the victim is forward, putting your hands on ■ Shutter windows securely and burned, provide first aid and call your knees. Do not lie flat on the brace outside doors. emergency medical assistance ground. immediately. Look for burns ■ Listen to a battery-operated radio where lightning entered and or television for the latest storm exited the body. If the strike information. If in a car: ■ Pull safely onto the shoulder of caused the victim’s heart and ■ Do not handle any electrical the road away from any trees that breathing to stop, give cardiopul- equipment or telephones because could fall on the vehicle. monary resuscitation (CPR) until lightning could follow the wire. medical professionals arrive and ■ Stay in the car and turn on the Television sets are particularly take over. emergency flashers until the dangerous at this time. heavy rains subside. Remember to help your neigh- ■ Avoid bathtubs, water faucets, ■ Avoid flooded roadways. bors who may require special and sinks because metal pipes can assistance — infants, elderly transmit electricity. people, and people with Estimating the Distance disabilities. If outdoors: from a Thunderstorm ■ Attempt to get into a building Report downed utility wires. Because light travels so much faster or car. than sound, lightning flashes can be seen Drive only if necessary. Debris ■ If no structure is available, get to long before the resulting thunder is and washed-out roads may an open space and squat low to the heard. Estimate the number of miles you make driving dangerous. ground as quickly as possible. (If are from a thunderstorm by counting the in the woods, find an area protected number of seconds between a flash of by a low clump of trees— never lightning and the next clap of thunder. Mitigation stand underneath a single large tree Divide this number by five. in the open.) Be aware of the Important: You are in danger Mitigation includes any activities that potential for flooding in low-lying from lightning if you can hear thunder. prevent an emergency, reduce the chance areas. Knowing how far away a storm is does of an emergency happening, or lessen the damaging effects of unavoidable ■ Kneel or crouch with hands on not mean that you’re in danger only emergencies. Investing in preventive knees. when the storm is overhead. mitigation steps now, such as installing ■ Avoid tall structures such as lightning rods to carry the electrical towers, tall trees, fences, telephone charge of lightning bolts safely to the lines, or power lines. Hail ground or purchasing flood insurance, ■ Stay away from natural lightning will help reduce the impact of severe Hail is produced by many strong rods such as golf clubs, tractors, thunderstorms in the future. For more thunderstorms. Hail can be smaller than fishing rods, bicycles, or camping information on mitigation, contact your a pea or as large as a softball and can be equipment. local emergency management office. very destructive to plants and crops. In a ■ Stay away from rivers, lakes, or hailstorm, take cover immediately. Pets other bodies of water. and livestock are particularly vulnerable to hail, so bring animals into a shelter.

EMERGENCY PUBLIC INFORMATION September 1993 BACKGROUNDER

THUNDERSTORMS AND LIGHTNING WHAT IS A THUNDERSTORM?

EMERGENCY INFORMATION A thunderstorm is formed from a 1. Thunderstorms can bring heavy rains (which can cause combination of moisture, rapidly flash flooding), strong winds, hail, lightning, and tornadoes. In rising warm air and a force a severe thunderstorm get inside a sturdy building and stay capable of lifting air such as a tuned to a battery-operated radio for weather information. warm and cold front, a sea breeze, or a mountain. All thunderstorms 2. Lightning is a major threat during a thunderstorm. In the contain lightning. Thunderstorms United States, between 75 and 100 Americans are hit and killed may occur singly, in clusters, or in each year by lightning. If you are caught outdoors, avoid natu- lines. Thus, it is possible for ral lightning rods such as tall, isolated trees in an open area or several thunderstorms to affect top of a hill and metal objects such as wire fences, golf clubs, one location in the course of a few and metal tools. hours. Some of the most severe 3. It is a myth that lightning never strikes twice in the same weather occurs when a single place. In fact, lightning will strike several times in the same thunderstorm affects one location place in the course of one discharge. for an extended time.

WHAT IS LIGHTNING?

Lightning is an electrical discharge that results from the buildup of positive and negative charges within a thunderstorm. When the buildup becomes strong enough, lightning appears as a “bolt.” This flash of light usually occurs within the clouds or between the clouds and the ground. A bolt of lightning reaches a temperature approaching 50,000 degrees Fahrenheit in a While thunderstorms and lightning can be found throughout the United States, they are split second. The rapid heating most likely to occur in the central and southern states. The state with the highest and cooling of air near the light- number of thunderstorm days is Florida. ning causes thunder. HELP YOUR COMMUNITY GET READY HOW THE PUBLIC CAN HELP The media can raise awareness about thunderstorms and lightning by providing AFTER A DISASTER important information to the community. Here are some suggestions: When disaster strikes, 1. Publish a special section in your local newspaper with people everywhere want to emergency information about thunderstorms and lightning. help those in need. To en- Place special emphasis on what people should do if they are sure that this compassion caught outside. Localize the information by printing the phone and generosity are put to numbers of local emergency services offices, the American Red Cross, and good use, the media can hospitals. highlight these facts:

2. Interview officials with the U.S. Department of Agriculture Financial aid is an immediate need of about the Federal Crop Insurance Corporation. disaster victims. Financial contribu-

3. Periodically inform your community of local public warning systems. tions should be made through a recognized voluntary organization to 4. Have your meteorologist speak to elementary schools and youth groups about help ensure that contributions are put thunderstorms, lightning and hail. to their intended use. 5. Interview a representative of the American Red Cross about Before donating food or clothing, wait giving first aid to people struck by lightning. for instructions from local officials. Immediately after a disaster, relief workers usually don’t have the time DID YOU KNOW... or facilities to setup distribution channels, and too often these items ■ ■ At any given moment, nearly More deaths from lightning go to waste. 1,800 thunderstorms are in occur on the East Coast. More progress over the surface of the forest fires are started in the Volunteers should go through a recognized voluntary agency such as earth. West as the lightning season the American Red Cross or Salvation coincides with the dry season ■ On average, the United States Army. They know what is needed there. and are prepared to deal with the gets 100,000 thunderstorms each need. Local emergency services ■ year. Approximately 1,000 Approximately 10,000 forest officials also coordinate volunteer tornadoes develop from these fires are started each year by efforts for helping in disasters. storms. lightning. Approximately Organizations and community groups $100 million in annual losses wishing to donate items should first ■ Large hail results in nearly result from forest and building $1 billion in damage to property contact local officials, the American fires caused by lightning. Red Cross, or Salvation Army to find and crops. out what is needed and where to ■ Straight-line winds exceeding ■ The power of lightning’s send it. Be prepared to deliver the 100 mph are responsible for items to one place, tell officials when electrical charge and intense most thunderstorm damage. you’ll be there, and provide for heat can electrocute on contact, transportation, driver, and unloading. split trees, ignite fires, and cause electrical failures.

EMERGENCY PUBLIC INFORMATION September 1993