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 signs:
Before a Severe Thunderstorm
- Dark, towering, or threatening clouds
- Distant lightning and thunder
Have disaster supplies on hand:
- Flashlight with extra batteries
- First aid kit and manual
- Non electric can opener
- Essential medicines
- Portable, battery-operated radio and extra batteries
- Emergency food and water
- Cash and credit cards
- Sturdy shoes
Check for hazards in the yard
Dead or rotting trees and branches can fall during a severe thunderstorm and cause injury and damage.
Make sure that all family members know how to respond after a thunderstorm
Teach family members how and when to turn off gas, electricity and water. Teach children how and when to call 9-1-1, police, fire department, and which radio station to tune for emergency information.
Learn how to respond to a tornado and flash flood
Tornadoes are spawned by thunderstorms and flash flooding can occur with thunderstorms. When a "severe thunderstorm warning" is issued, review what actions to take under a "tornado warning" or a "flash flood warning."
Develop an emergency communication plan
In case family members are separated from one another during a thunderstorm (a real possibility during the day when adults are at work and children are at school), have a plan for getting back together. Ask an out-of-state relative or friend to serve as the "family contact". After a disaster, it's often easier to call long distance because of busy circuits. Make sure everyone knows the name, address, and phone number of the contact person. Contact your local emergency management office or American Red Cross chapter for more information on thunderstorms and lightning.
If you are outdoors during a severe thunderstorm:
- Seek shelter immediately.
- Secure outdoor objects such as lawn furniture that could blow away or cause damage or injury before a storm approaches.
- Take light objects inside prior to the storm.
- Shutter windows securely and brace outside doors.
- Listen to a battery operated radio or television for the latest storm information.
- Do not handle any electrical equipment or telephones because lightning could follow the wire. Television sets are particularly dangerous at this time - unplug electrical devices.
- Avoid bathtubs, water faucets, and sinks because metal pipes can transmit electricity.
If in a car:
- Seek shelter indoors immediately.
- If no structure is available, get to an open space an squat low to the ground as quickly as possible. (If in the woods, find an area protected by low clump of trees--never stand underneath a single large tree in the open.) Be aware of the potential for flooding in low-lying areas.
- Crouch with hands on knees.
- Avoid tall structures such as towers, tall trees, fences, telephone lines, or power lines.
- Stay away from natural lightning rods such as golf clubs, tractors, fishing rods, bicycles, or camping equipment.
- Stay away from rivers, lakes, or other bodies of water. Flash floods are possible.
- If you are isolated in a level field or prairie and you feel your hair stand on end (which indicates that lightning is about to strike), bend forward, putting your hands on your knees. A position with feet together and crouching while removing all metal objects is recommended. Do not lie flat on the ground. Make yourself as small as possible.
Estimating the Distance from a Thunderstorm
- Pull safely onto the shoulder of the road away from any trees that could fall on the vehicle.
- Stay in the car and turn on the emergency flashers until the heavy rains subside.
- Avoid flooded roadways. Turn around, don't drown. Moving water across roadways can sweep/float a car into deeper water. It only takes a couple feet of water to move a car.
Because light travels much faster than sound, lightning flashes can be seen long before the resulting thunder is heard. Estimate the number of miles you are from a thunderstorm by counting the number of seconds between a flash of lightning and the next clap of thunder. Divide this number by five. Important: You are in danger from lightning if you can hear thunder. Knowing how far away a storm is does not mean that you're in danger only when the storm is overhead.
Hail is produced by many strong thunderstorms. Hail can be smaller than a pea or as large as a softball and can be very destructive to plants and crops. In a hailstorm, take cover immediately. Pets and livestock are particularly vulnerable to hail, so bring animals into a shelter. Hail in a severe thunderstorm almost always always proceeds tornados.
After a Severe Thunderstorm
Check for injuries - A person who has been struck by lightning does not carry an electrical charge that can shock other people. If the victim is burned, provide first aid and call emergency medical assistance immediately. Look for burns where lightning entered and exited the body. If the strike causes the victim's heart and breathing to stop, give cardiopulmonary resuscitation (CPR) until medical professionals arrive and take over. Remember to help your neighbors who may require special assistance--infants, elderly people, and people with disabilities. Always call for help first (911) before starting CPR or medical aide.
Report downed utility wires
Drive only if necessary - Debris and washed-out roads may make driving dangerous.
Mitigation - Mitigation includes any activities that lessen the effects of an emergency, reduce the chance of an emergency happening, or lessen the damaging effects of unavoidable emergencies. Investing in preventive mitigation steps now, such as installing lightning rods to carry the electrical charge of lightning bolts safely to the ground or purchasing flood insurance, will help reduce the impact of severe thunderstorms in the future.
For more information on mitigation, contact your local emergency management office.