Protect yourself from killer tornadoes
By Lamar James
Extension Communications Specialist
What You Can Do Before the Storm ?
Develop an emergency storm plan for all family members whether at home, work, school or outdoors.
Teach children their county and neighboring counties because storm alerts are given by counties. Keep highway maps in several convenient locations to follow storm movements given by weather bulletins.
Conduct frequent storm drills.
Have a NOAA Weather Radio with a battery back-up and warning alarm to receive warnings.
Listen to TV or radio for weather updates.
If your activity is outdoors, listen to the latest forecasts and take necessary precautions (possibly delaying activities until the danger is past) during threatening weather.
If a Tornado Warning is Issued or Threatening Weather Approaches:
Move to a previously designated safe area, preferably a basement.
If an underground shelter is not available, move to an interior room or hallway on the lowest floor. Crouching under a sturdy desk or rugged furniture is advisable if they are located near a central wall. Place pillows or blankets over your head and upper body for extra protection.
Stay away from doors and windows.
Do not try to outrun a tornado in your car. Instead, leave it immediately. If caught outside or in a vehicle, get out and lie flat in a nearby ditch or depression.
Do not take shelter under highway overpasses.
If a tornado strikes, watch out for fallen power lines. Stay out of damaged areas until power is disconnected to avoid accidental electrical shock.
Know the Difference Between a Tornado Watch and a Tornado Warning
TORNADO WATCH. . . Tornadoes are possible in your area. Remain alert for approaching storms.
Listen to NOAA Weather Radio, commercial TV or radio for weather information.
TORNADO WARNING. . . A tornado has been sighted or indicated by weather radar. If you may be in the path of the storm, move to a previously designated safe area.
Tornado watches and warnings are issued as soon as the conditions are identified. Use the available time, once you note a warning, to prepare for one of nature’s most destructive storms. Stay informed about the approaching storm.
Sometimes tornadoes develop so rapidly that advance warning is not possible. Remain alert for signs of an approaching tornado.
Do you know that new Doppler radar units can detect tornadoes that are forming?
Doppler radar measures wind speeds and the direction of air currents within storms. This capability really enhances identification because a tornado is simply a violently rotating column of air, pendant from a cumulonimbus (thunderstorm) cloud. Conventional radar gave only rainfall intensity and “storm conditions.” Doppler radar capabilities improve the accuracy and timeliness of National Weather Service bulletins.
Doppler radar units are located at National Weather Service offices in Little Rock and Fort Smith, Arkansas; Memphis, Tennessee; Tulsa, Oklahoma; Jackson, Mississippi; Shreveport, Louisiana; and Springfield, Missouri.
Tornadoes occur in many parts of the world. However, three-fourths of the world’s tornadoes occur in the U.S. These violent storms occur most frequently in the United States east of the Rocky Mountains during the spring and summer months. Arkansas is located in the lower Mississippi Valley where warm, moist air flowing northward from the Gulf of Mexico interacts with cool, dry air spreading southward and eastward from the Great Plains.
During the 50 years from 1950-1999, 1,073 tornadoes have struck Arkansas. Records show that they can occur any day of the year and any time of day. Tornado preparation requires constant vigilance.
While tornadoes in Arkansas normally occur during the spring and fall months, they can occur in any month. A total of 68 tornadoes occurred in January, 1999. This set a national record for the greatest number of tornadoes in the month of January.
During 1999, 107 tornadoes were sighted, setting a new record for Arkansas.
Tornadoes occur with greater frequency during late afternoon to late evening, according to the National Weather Service records. In Arkansas, five in the afternoon is the time of the maximum tornado incidence.
The greater tornado frequency during afternoons and evenings can largely be explained from patterns of increased instability in the atmosphere. This air instability results from a buildup of heat near the earth’s surface on warm afternoons. After sunset the layer of heated air near the earth’s surface begins to cool. This usually restores more atmospheric stability and reduces the threat of tornadoes.
Any period of unseasonably warm and humid conditions should trigger caution about the possibility of a tornado. Monitor weather bulletins and watch the sky during approaching thunderstorms. Violently moving clouds indicate high air velocities which may develop into a tornado.
Tornadoes have killed a total of 1,503 Arkansans since 1880. A “killer” tornado is a tornado that causes the death of at least one person. The worst killer storms in the state’s history occurred March 21, 1952. That day three tornadoes killed 111 persons and injured an additional 772. In recent years, an average of five Arkansans have died from tornadoes each year.
Recognizing conditions that may develop into tornadic winds is the first major step in avoiding this cruel disaster. Weather broadcasts can help avert tragedy. Be prepared to find suitable protection. Flying debris from tornadoes cause most deaths and injuries. Most tornado damage is probably caused by winds of 125 mph; however, maximum wind velocities may exceed 250 mph. The most damaging storm occurred in the Fort Smith-Van Buren areas on April 21, 1996, with associated costs around $300 million.
Surface winds in connection with developing tornadoes are usually from the southwest. Sixty-four percent of the tornadoes in Arkansas move from the southwest to the northeast. But tornadoes can come from any direction. Some tornadoes have stopped their forward movement, turned, and looped back across their path. Their average speed of advance is 30 mph, but a few move as fast as 70 mph.
The diversity of their approach patterns and speed demands alertness, especially after a tornado warning has been issued for your area. Refrain from driving to locate family or friends. Make phone calls to notify those who may have missed the tornado warning broadcast, but keep an alert eye on the sky.
Violent storms associated with low barometric pressures can spawn a tornado. Strong winds in the lower few thousand feet of the atmosphere may be noted by cloud movements. The storm cells develop from 20,000 to 40,000 feet elevation. Rotation of air (cloud movement) usually starts with a circulation near 20,000 feet and builds up and down.
Tornadoes often form near a thunderstorm’s updraft. Often surface winds of 25-35 miles per hour are noted near a developing tornado. Small clouds will rise quickly into the larger cloud layer. Near a tornado the barometric pressure drops rapidly. The characteristic funnel may drop down, loop and appear to dissipate at times.
If a funnel is sighted, take shelter immediately. Tornadoes can reach you within a few minutes. Other funnels can spawn directly overhead.
Tornadoes may “mature” in a classic fashion. However, be aware that violent storm cells can cause two or more circulations. It is important to have a good view of the entire sky to avoid being surprised by another funnel that was obscured behind a ridge, buildings or a row of trees.
Any time you are observing a storm, be alert to the potential of being struck by lightning. Standing near a tree or house that projects above the landscape during violent weather risks being in a deadly path of lightning discharge. Any vertical projections, especially metal structures, can readily attract a fatal electrical current.
Tornadoes occur all over Arkansas. It is important to have a tornado plan and review it annually. If changes in a community warning system have occurred or a better shelter is now available nearby, take advantage of the new opportunities. Steps to survive a tornado are simpler and more important than earthquake precautions.
Everyone should have a disaster plan to survive a tornado. Follow these basic steps to develop a family tornado disaster plan:
- Find out if your community has tornado warning sirens. Learn your community’s warning signals and evacuation plans. Locate the safest areas in your home. To be better prepared for a tornado, contact your local National Weather Service office, local Office of Emergency Management, American Red Cross Chapter or county Cooperative Extension office to determine what they can provide.
- Meet with your family to create a plan. Discuss the tornado warning measures available to you. Point out the safest areas in your home to assure that everyone knows where to go for shelter.
- Practice emergency drills and maintain your plan. Ask questions to make sure each family member remembers the meeting place. Assemble in the assigned tornado shelter. Remind each one to use the telephone only if there is no immediate danger and then only to notify other family members of the violent weather concern or tornado watch. Post emergency phone numbers and safety rules by the telephone. Teach children how and when to call 911 or the local emergency medical service number.
- Improve your plan. (a) Review the emergency phone numbers posted by the telephones. (b) Install fire extinguishers and make other safety improvements to your house. (c) Teach your family how to use a fire extinguisher and how and when to turnoff water, gas and electricity. (d) Review basic safety measures and/or enroll in CPR and first aid classes. (e) Maintain supplies in your home to meet your emergency needs for at least three days. Assemble a disaster supply kit with items needed for an evacuation. Store these supplies in sturdy, easy-to-carry containers such as backpacks or duffel bags.
- Protect valuable records. Maintain a safety-deposit box for family and business papers that cannot be replaced. Review specific wind and flood damage protection provided by your insurance policy. Prepare records that will help verify losses for insurance, tax or federal disaster declarations.
- Test and recharge (as needed) your fire extinguishers according to the manufacturer’s instructions. Replace stored water every six months.
School Disaster Plans
(Hospitals, nursing homes and other institutions should develop similar plans.)
Develop a severe weather action plan and have frequent drills.
- Assign responsibility for activating the severe weather plan. This includes assuring severe weather is continually monitored with NOAA Weather Radio and local TV/radio.
- Make sure several leaders know how to turn off electricity and gas in the event the school is damaged.
- Each school structure should be inspected and tornado shelter areas designated by a registered engineer or architect. Schools without basements should use interior rooms and hallways on the lowest floor and away from windows.
- If the primary power for the school’s alarm is electricity, provide a charged-battery backup or have a compressed air horn or megaphone to activate the alarm during power outages.
- Have provisions for disabled students and those in portable classrooms.
- Move students quickly into interior rooms or hallways on the lowest floor. Have them assume the tornado protection position.
- Lunches, classes, or assemblies in large, free-span cafeterias or auditoriums should be delayed if severe weather is anticipated.
- Do not remain in auditoriums, cafeterias, gymnasiums or other structures with wide, free-span roofs because they offer no protection from tornado-strength winds.
- Keep children at school beyond regular hours if threatening weather is expected. Children are safer at school than in a bus or car. Students should not be sent home early if severe weather is approaching.
NOAA Weather Radio
Weather information can be received 24 hours a day from NOAA Weather Radio. In Arkansas, this is a joint effort between the National Weather Service and the state. The latest weather information is broadcast all day and all night, including severe weather details.
Special radio receivers are available at radio shops, electronics stores, department stores and discount stores. Many multiband radios and scanners can also receive the frequencies.
Some radio receivers have a “warning alarm” feature for severe weather watches or warnings that allows the National Weather Service to automatically turn on the radio, day or night. This warning alarm is tested each Wednesday between 11 a.m. and noon. If bad weather is occurring or is forecast, the test is postponed until the next good-weather day.
Transmitter Locations and Assigned Frequencies (mhz)
Tornado Safety Locations
Homes With Basements
Seek refuge near the basement wall in the most sheltered and deepest part of the basement below ground.
Homes Without Basements
Take cover in the smallest room with stout walls, or under heavy furniture, or a tipped-over, sturdy upholstered couch or chair near the center of the house. The first floor is safer than the second or third.
Don’t take time to open or close windows; get away from them and go to a safe area immediately. Construction of a storm cellar is particularly advisable for those in homes without basements.
Mobile Homes and Modular Buildings
Abandon mobile homes. Arrange for use of a convenient safe area in advance, should violent weather occur.
Consider basements, a storm cellar, the ground floor of a sturdy structure or a nearby culvert or deep ditch.
Factories, Auditoriums and Other Large Buildings With Wide, Free-Span Roofs
These buildings are particularly vulnerable to tornadic wind damage due to the large roof expanse upon which wind forces act and the distance between roof-supporting walls. Basements of these buildings offer reasonably good protection. Smaller interior rooms at ground level or nearby sturdy buildings are options, depending on their construction and the urgency for shelter. Pre-select and mark designated safe areas. Hold tornado safety drills. Train building employees to direct occupants to designated safe areas. Trained spotters should assume their posts as soon as conditions become threatening.
The basement or an interior hallway on a lower floor of an office building is safest. Upper stories are unsafe.
If there is not time to reach one of the lower floors, a small room with stout walls (closet or bathroom) or an inside hallway provides some protection against flying debris. Otherwise, getting under heavy furniture must do. Select and mark designated safe areas in office buildings. Train employees to direct the occupants to designated areas.