Tornado

WHAT IS A TORNADO?

A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. It is spawned by a thunderstorm (or sometimes as a result of a hurricane) and produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly. The damage from a tornado is a result of the high wind velocity and wind-blown debris. Tornado season is generally March through August, although tornadoes can occur at any time of year. They tend to occur in the afternoons and evenings: over 80 percent of all tornadoes strike between noon and midnight.

DANGER ZONES

Tornadoes can occur in any state but are more frequent in the Midwest, Southeast and Southwest. The states of Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, Nebraska, Oklahoma, South Dakota, and Texas are at greatest risk.

Tornadoes have occurred at various times in parts of Massachusetts. The worst such disaster was the Worcester tornado of 1953. Occurrences in recent years include the tornado in Great Barrington in May, 1995, and a “down burst” in the Brockton area in May, 1996.

EMERGENCY INFORMATION

The best protection during a tornado is in an interior room on the lowest level of a building, preferably a basement or storm cellar.

Tornadoes strike with incredible velocity. Wind speeds may approach 300 miles per hour. These winds can uproot trees and structures and turn harmless objects into deadly missiles, all in a matter of seconds. Mobile homes are particularly vulnerable to tornadoes.

Injury or deaths related to tornadoes most often occur when buildings collapse, people are hit by flying objects or are caught trying to escape the tornado in a car.

Tornadoes are most destructive when they touch ground. Normally a tornado will stay on the ground for no more than 20 minutes; however, one tornado can touch ground several times in different areas.

DID YOU KNOW?

Tornadoes can be nearly invisible, marked only by swirling debris at the base of the funnel. Some are composed almost entirely of windblown dust and still others are composed of several mini-funnels. On average, the United States experiences 100,000 thunderstorms each year. Approximately 1,000 tornadoes develop from these storms. Although tornadoes do occur throughout the world, the United States experiences the most intense and devastating tornadoes.

Tornadoes produce the most violent winds on earth. Tornado winds can approach speeds as high as 300 miles per hour, travel distances over 100 miles and reach heights over 60,000 feet above ground. In November 1988, 121 tornadoes struck 15 south central states, resulting in 14 lives lost and damages reaching $108 million. According to the National Weather Service, about 42 people are killed because of tornadoes each year.

FACT SHEET

When a tornado is coming, you have only a short amount of time to make life-or-death decisions. Advance planning and quick response are the keys to surviving a tornado.

BEFORE
  • Designate an area in the home as a shelter, and practice having everyone in the family go there in response to a tornado threat.
  • Discuss with family members the difference between a “tornado watch” and a “tornado warning.”
  • For additional information: Please contact the New Bedford Emergency Management Department (991-6386), if you are a New Bedford resident, or your local emergency management (or civil defense) department.
  • Have disaster supplies on hand. Flashlight and extra batteries portable, battery-operated radio, extra batteries, first aid kit, manual emergency food, water, nonelectric can opener, essential medicines, cash, credit cards, sturdy shoes
  • Develop an emergency communication plan. In case family members are separated from one another during a tornado (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. Make sure everyone in the family knows the name, address, and phone number of the contact person.
  • Tornado Watches and Warnings a tornado watch is issued by the National Weather Service when weather conditions are such that tornadoes are likely to develop. This is time to remind family members where the safest places within your home are located, and listen to the radio or television for further developments.
  • A tornado warning is issued when a tornado has been sighted or indicated by radar. The danger is very serious and everyone should go to a safe place, turn on a battery-operated radio and wait for further instructions.
  • Mobile homes are particularly vulnerable. A mobile home can overturn very easily even if precautions have been taken to tie down the unit. When a tornado warning is issued, take shelter in a building with a strong foundation. If shelter is not available, lie in ditch or low-lying area a safe distance away from the unit.
  • Learn these tornado danger signs: Large hail: Tornadoes are spawned from powerful thunderstorms and the most powerful thunderstorms produce large hail. Tornadoes frequently emerge from near the hail-producing portion of the storm. Calm before the storm: Before a tornado hits, the wind may die down and the air may become very still. Cloud of debris: An approaching cloud of debris can mark the location of a tornado even if a funnel is not visible. Funnel cloud: A visible rotating extension of the cloud base is a sign that a tornado may develop. A tornado is evident when one or more of the clouds turns greenish (a phenomenon caused by hail) and a dark funnel descends. Roaring noise: The high winds of a tornado can cause a roar that is often compared with the sound of a freight train. Calm behind the storm: Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.
DURING

If at home:

  • Go at once to the basement, storm cellar, or the lowest level of the building.
  • If there is no basement, go to an inner hallway or a smaller inner room without windows, such as a bathroom or closet.
  • Get away from the windows.
  • Go to the center of the room.
  • Stay away from corners because they tend to attract debris.
  • Get under a piece of sturdy furniture such as a workbench or heavy table or desk and hold on to it.
  • Use arms to protect head and neck.
If in a mobile home:
  • Get out and find shelter elsewhere.
If at work or school:
  • Go to the basement or to an inside hallway at the lowest level.
  • Avoid places with wide-span roofs such as auditoriums, cafeterias, large hallways, or shopping malls.
  • Get under a piece of sturdy furniture such as a workbench or heavy table or desk and hold on to it.
  • Use arms to protect head and neck.
If outdoors:
  • If possible, get inside a building.
  • If shelter is not available or there is no time to get indoors, lie in a ditch or low-lying area or crouch near a strong building.
  • Use arms to protect head and neck.
If in a car:
  • Never try to outdrive a tornado in a car or truck. Tornadoes can change direction quickly and can lift up a car or truck and toss it through the air.
  • Get out of the car immediately and take shelter in a nearby building.
  • If there is no time to get indoors, get out of the car and lie in a ditch or low-lying area away from the vehicle.
  • Be aware of the potential for flooding.
AFTER
  • Help injured or trapped persons.
  • Give first aid when appropriate. Don’t try to move the seriously injured unless they are in immediate danger of further injury. Call for help.
  • Turn on radio or television to get the latest emergency information.
  • Stay out of damaged buildings. Return home only when authorities say it is safe.
  • Use the telephone only for emergency calls.
  • Clean up spilled medicines, bleaches, or gasoline or other flammable liquids immediately. Leave the buildings if you smell gas or chemical fumes.
  • Take pictures of the damage–both to the house and its contents–for insurance purposes.
  • Remember to help your neighbors who may require special assistance–infants, the elderly, and people with disabilities.
INSPECTING UTILITIES IN A DAMAGED HOME
  • Check for gas leaks–If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building. Turn off the gas at the outside main valve if you can and call the gas company from a neighbor’s home. If you turn off the gas for any reason, it must be turned back on by a professional.
  • Look for electrical system damage–If you see sparks or broken or frayed wires, or if you smell hot insulation, turn off the electricity at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician first for advice.
  • Check for sewage and water lines damage–If you suspect sewage lines are damaged, avoid using toilets and call a plumber. If water pipes are damaged, contact the water company and avoid using water from the tap. You can obtain safe water by melting ice cubes.
MITIGATION

Mitigation includes any activities that prevent 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 checking local building codes and ordinances about wind-resistant designs and strengthening unreinforced masonry, will help reduce the impact of tornadoes in the future. For more information on mitigation, contact your local emergency management office.

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