Radar Technology and Predicting Dangerous Tornadoes
Radar Technology and Predicting Dangerous Tornadoes
Tornadoes are among the most terrifying forces of nature and can sometimes occur in all of the lower 48 states in the United States during a one year period. I was eight years old when I experienced the scary moment of seeing a dangerous tornado for the first time. Even though most tornadoes occur in the United States, if there is the right combination of weather conditions then twisters can technically develop anywhere in the world including parts of Europe. (Spilsbury 10) Most twisters in the United States occur in Tornado Alley, which includes seventeen states in the middle and south central part of the country. (Prokos 16) In the right wind and weather environment, tornadoes can appear at any time of the day or night, but most twisters occur in the afternoon or early evening between 3pm and 7pm. This is the time of day when the sun has warmed up the ground and produces the hot muggy air, which is needed to create a tornado. Twisters can develop at any time of the year, although they occur more in the United States during spring, summer, and early fall months. Radar technology helps meteorologists understand how the tornadoes develop, rate the tornadoes by using the Enhanced Fujita scale, calculate the levels of destruction caused by the wind speeds, and by alerting people to take safety when dangerous and possibly deadly tornadoes arrive in the area.
The United States has about 100,000 thunderstorms a year, which causes between 800 and 1,000 tornadoes, and more than 100 people are killed by tornadoes every year. Most tornadoes occur in the southern United States during April and May, but twisters which develop in late fall and early winter months cause the most extreme destruction. The Great Plains area has seven out of ten of all the tornadoes that happen on Earth. (Spilsbury 11) The most dangerous F5 twisters usually occur in Texas, Kansas, and Oklahoma. Tornadoes have even occurred in the large cities of Nashville, St. Louis, New York, Miami, Atlanta, Salt Lake City, Memphis, and Chicago. (AMS 201) Even national monuments in big cities can suffer damage from the disastrous twisters and the powerful thunderstorms that travel through the city. Wisconsin has experienced a few rare events of powerful and destructive F5 tornadoes and even had some twisters which developed during the winter months.
The state of Wisconsin experienced a rare event on January 7, 2008. In fact, a winter tornado had only happened once before in Wisconsin between 1950 and 2007, when an F3 twister affected parts of Green and Rock Counties on January 24, 1967. (NWS) That afternoon, a warm, moist, and unstable air mass, with temperatures rising into the lower 60s, moved into Southeast Wisconsin. This unusual weather created thunderstorms just ahead of a stationary front and produced hail, damaging winds, and a few tornadoes. The first tornado was rated an EF3, which spun up in southeast Walworth County, and then tracked through the Wheatland and Brighton areas of western Kenosha County. The second tornado was rated EF1 and occurred in the town of Somers and on the north side of the city of Kenosha. The National Weather Service had written an article regarding the important details of these twisters and the destruction.
July 18, 1996 will be a day I will never forget, because of the dangerous F5 tornado which destroyed the city of Oakfield. Oakfield is about fifteen miles away from Waupun, which is the city where my parents live. On this day, I was ten years old and this was the second time in my life that I had experienced a dangerous tornado. A violent twister struck the village of Oakfield at about 6:15pm, after it touched down four miles WNW of the village. (NWS) During its approach on Oakfield, the tornado had increased to a F3 rating, but when it tore through the village, the twister had intensified to a F4. However, along the path one to four miles east of the village, the tornado increased to F5 strength (estimated 265 mph winds). Prior to entering Oakfield, the tornado hopped and skipped a few times, and multiple vortices were observed at times during its life cycle. The National Weather Service had written an article regarding the important details of this tornado and the destruction.
The Oakfield Tornado will be remembered by the hundreds of people who lost their homes or businesses, and all the local communities within 25 miles which dealt with this devastating event. The core width of the most intense damage was about 150 to 200 yards, although at times, some secondary damage was observed in a 400 yard wide path. (NWS) Miraculously, no one was killed, but there were twelve injured people which needed to be hospitalized for severe injuries. Along the tornadoes path, 60 homes and six businesses were destroyed, but an additional 130 homes and businesses were damaged in the area. In the rural areas along the tornadoes path, eighteen barns and many sheds were destroyed or damaged, and about 500 acres of crops were wiped out. The total damage amounts were $39.5 million in public/private property, and $900,000 in crop losses. Oakfield residents heard local sirens about eight minutes before the tornado entered the village. The residents of Oakfield were extremely lucky that day to only incur destruction and not death.
The state of Wisconsin experienced a significant tornado event on August 18, 2005. This will be a day I will never forget, because my 20th birthday was the day before. 27 tornadoes occurred in Wisconsin, setting a new record for most tornadoes developing in the state in a single day. The previous record of 24 tornadoes was set on May 8, 1988. (NWS) On August 18, a powerful F3 tornado developed near Fitchburg, and travelled about twenty miles through Dane and Jefferson Counties. The twister passed through Stoughton with maximum intensity and a width of one–half mile. In Stoughton, the tornado completely destroyed or damaged 240 houses, left property damage of $44 million, killed one person, and injured 23 other people. The National Weather Service had written an article regarding the important details of this tornado outbreak and all of the destruction.
Tornadoes are rated from EF–0 to EF–5 on the Enhanced Fujita Scale, when examining the amount of destruction to determine how fast the winds were spiraling inside the storm. Ted Fujita invented the original Fujita Scale in 1971, which was updated in 2007 to become the Enhanced Fujita Scale; the updated scale uses more details about specific kinds of structures damaged and how the damaged buildings were built, when determining a more precise rating of twisters. (Carson 25) EF–0 has 65 to 85 mph wind gusts and light damage: damage to shingles on roofs and siding on houses. EF–1 has 86 to 110 mph wind gusts and moderate damage: lots of roof damage, uproot trees, tip over mobile homes, and bend flagpoles. EF–2 has 111 to 135 mph wind gusts and considerable damage: most mobile homes destroyed, permanent homes shift off foundations, flagpoles collapse, and bark blown off softwood trees. EF–3 has 136 to 165 mph wind gusts and severe damage: bark blown off hardwood trees and most portions of houses destroyed. EF–4 has 166 to 200 mph wind gusts and devastating damage: complete destruction of well–built homes and sections of school buildings. EF–5 has more than 200 mph wind gusts and incredible damage: significant destruction to mid–rise and high–rise buildings.
Tornadoes develop from powerful thunderstorms and occur when warm, wet winds from one direction meet colder, dryer winds moving in the opposite direction. When these two kinds of winds meet, the warm air rises over the cold air and begins to spin, which creates the start of a twister. The funnel of the tornado is the long spiraling part, which stretches from the storm cloud to the ground. Funnels typically grow about 660 feet (200 meters) wide. Small tornadoes stay on the ground for less than five minutes and move at 10 to 20 miles per hour. Most twisters last about 20 minutes on the ground and travel less than 15 miles, before the powerful storm systems begin to weaken. Large and powerful tornadoes can remain on the ground continuously for over one hour.
The thunderstorms which produce twisters bring heavy showers of rain, thunder, lightning, and sometimes even large hailstones. A severe thunderstorm has at least one of the following: winds faster than 58 miles per hour, hail larger than 3/4 of an inch across, or tornadoes. (Williams 179) A tornado outbreak occurs when more than six twisters develop in one area during a 48–hour period. (Prokos 10) During an outbreak, the National Weather Service can receive reports regarding dozens of tornadoes which may sweep through several states at the same time on one day. Some twisters grow so big that they create other smaller tornadoes from one storm cloud. (Spilsbury 7) Low thunderstorm clouds sometimes hide approaching twisters. Tornadoes come in different sizes, shapes, and even colors. A twister gets its color from the dirt, debris, or cloudy air which it is twirling in the funnel. A tornado’s direction and wind speed can change at any time, and sometimes the alteration occurs suddenly, before the National Weather Service can detect the change through radar technology. Radar images show the severity of thunderstorms and can help scientists predict possible tornadoes. The National Weather Service has three safety alerts regarding tornadoes that are issued when necessary. A Tornado Watch is issued when thunderstorms could possibly produce a tornado. A Tornado Warning occurs when a tornado has been sighted or indicated by weather radar, and requires people to take immediate shelter. A Tornado Emergency happens in rare cases involving a possible F5 tornado, which would be a large, violent twister that is expected to hit a populated area, resulting in numerous deaths, and causing total destruction. If a Tornado Emergency develops, all people need to seek shelter below ground or in a tornado safe shelter if possible.
Dangerous winds of a tornado can cause severe damage to homes, buildings, and transportation objects, completely destroy small cities, and even result in the deaths of innocent people. Many of the people killed in tornadoes die when objects hit them, which were thrown through the air by these terrible winds. The deadly winds of a tornado can blow over walls, mobile homes, cars, and trains, while also snapping overhead cables and power lines. Damaged power lines can result in electrocuting people and starting fires. A twister can have several strong wind funnels within the main tornado funnel. Therefore, some houses and buildings will be completely destroyed, while houses or buildings on the next street might have little or no damage. A tornado’s funnel can stretch the distance of a few blocks to a few miles, which can reveal the amount of destruction in any city. The winds in the funnel of a twister can suck up anything and drop the object miles away from the original location. A twister moves like a spinning top, when the winds in the funnel spin round and round at the same time that the tornado travels across a stretch of land. “Extremely destructive tornadoes can have winds up to 300mph, be 10 miles wide, and plow a damaging path at 60 mph for over an hour. Most tornadoes have milder winds, leave paths of damage less than 1,600 feet wide, and move at speeds of 35mph or less for about 10 minutes.” (Carson 10) “Two out of every hundred tornadoes have spinning winds of over 205 miles per hour.” (Spilsbury 6)
Supercells are powerful thunderstorms, which need four main ingredients to produce a tornado: moisture, instability, lift, and wind shear. (Carson 12) These types of powerful thunderstorms are full of strong updrafts of hot air and powerful downdrafts of sinking cold air. Wind shear happens when wind at one height is moving in a different direction or speed than wind at another height in the storm cloud. Only about 20 percent of supercell thunderstorms produce destructive F5 tornadoes. Supercell thunderstorms are big and dangerous, can last for hours, and can produce F5 tornadoes. Supertwisters are deadly and destructive EF–5 tornadoes, which cause 67 percent of tornado deaths in the United States. Despite great progress over the past several years, scientists are still learning how supercells concentrate enormous amounts of energy and give air the violent swirling motions of destructive tornadoes. (Williams 186)
Tornadoes are natural disasters which cannot be stopped, even though meteorologists are developing ways to weaken the storm and decrease the amount of destruction. Scientists can reduce the total amount of damage caused by a thunderstorm or twister by studying radar and working with storm chasers to predict powerful storms earlier. Only about half of all tornadoes can be spotted in time to warn people about them. Meteorologists are also working on ways to stop powerful twisters from forming, including “firing dry ice into growing storms which should weaken the storm system, by dropping more rain and decreasing the winds.” (Spilsbury 28) In this way, scientists might be able to stop a storm from producing dangerous and deadly F4 or F5 tornadoes. Often, large thunderstorms don’t create as many twisters as small storms do, but a bigger storm system increases the chance of a F4 or F5 tornado to develop. In the future, meteorologists hope to develop new ways to predict destructive thunderstorms and dangerous tornadoes sooner, and find new ways to alert people faster to take shelter in secure locations. People can currently receive weather notifications through text messaging on cell phones and on social networking sites like Facebook and Twitter.
ARX Webmaster. “Tornado Outbreak of August 18, 2005.” National Weather Service. N.p., 26 Aug. 2005. Web. 2 Dec. 2010.
Carson, Mary Kay. Inside Tornadoes. New York: Sterling, 2010. Print.
MKX Webmaster. “January 7, 2008 - Tornadoes in Far Southeast Wisconsin.” National Weather Service. N.p., 23 Apr. 2008. Web. 2 Dec. 2010.
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Prokos, Anna. “Tornado Alley.” The Ultimate 10 Natural Disasters: Tornadoes. Pleasantville: Gareth Stevens, 2009. 16. Print.
Spilsbury, Louise and Richard. Awesome Forces of Nature: Terrifying Tornadoes. Chicago: Heinemann Library, 2010. Print.
Williams, Jack. The American Meteorological Society Weather Book: The Ultimate Guide to America’s Weather. Chicago: American Meteorological Society, 2009. Print.