What is the Fujita Scale for tornadoes? Wind Speed Scale

Tornadoes are one of the most powerful and devastating natural disasters on the planet. Understanding their intensity is crucial for predicting their impact and taking appropriate safety measures. In 1971, Dr. Tetsuya Theodore Fujita introduced a scale to measure tornado intensity, known as the Fujita Scale. This scale, often referred to as the F-scale, categorizes tornadoes based on the damage they cause, providing valuable insights into their strength and potential impact. By decoding the Fujita Scale, individuals, communities, and meteorologists can gain a better understanding of tornado intensity levels and make informed decisions to protect lives and property.

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How the Fujita Scale measures tornado intensity

The Fujita Scale measures tornado intensity by assessing the damage caused to structures and vegetation. This damage is then correlated with wind speeds to determine the tornado’s strength. The scale consists of six levels, ranging from F0 to F5, with each level representing a specific range of estimated wind speeds and associated damage. For example, an F0 tornado is characterized by light damage, such as broken tree branches and minor roof damage, while an F5 tornado causes catastrophic destruction, including the leveling of well-constructed houses and the sweeping away of large objects. By analyzing the extent of damage, meteorologists can estimate the wind speeds and assign an appropriate Fujita Scale rating, enabling accurate classification of tornado intensity.

The history and evolution of the Fujita Scale

The Fujita Scale has a rich history and has undergone several revisions and improvements since its inception. Dr. Tetsuya Theodore Fujita developed the scale in collaboration with his wife, Dr. Sumiko Fujita, to provide a standardized method for categorizing tornadoes based on their impact. Over the years, the scale has been refined to incorporate advancements in meteorological research and technology, leading to more precise assessments of tornado intensity.

In 2007, the Enhanced Fujita Scale (EF-Scale) was introduced to replace the original Fujita Scale, taking into account additional factors such as construction quality and building codes to better reflect modern infrastructure. This evolution reflects the ongoing efforts to enhance the accuracy and reliability of tornado intensity measurement, ultimately improving the ability to assess and respond to these natural phenomena.

Fujita Scale
Credit: University of Chicago

How was the Fujita Scale created?

Tornadoes have been observed on all continents, but the mainland United States usually experiences more tornadoes annually than any other place in the world due to its geography. Before the mid-20th century, our comprehension of their mechanisms, formation, and prediction was quite limited. Despite their devastating potential, tornadoes occur relatively infrequently and with little warning, making them challenging to study. Forecasting started to advance, particularly with the wider use of radar after World War II, but obtaining even basic knowledge was a formidable task.

Professor Tetsuya “Ted” Fujita, also known as “Mr. Tornado” due to his exceptional understanding of thunderstorms, tornadoes, and microbursts, entered the scene amidst the chaos. He recognized the necessity of categorizing tornadoes and proposed a method to do so by assessing the damage on a scale from 0 to 5. In his 1971 publication, “Proposed Characterization of Tornadoes and Hurricanes by Area and Intensity,” Fujita introduced a scale to measure tornado intensity, correlating estimated wind speeds with the Beaufort Wind Scale and the resulting damage. This scale was based on numerous ground and aerial tornado-damage surveys conducted by Fujita.

For instance, if a tornado has wind speeds ranging from 207 to 260 miles per hour, resulting in severe destruction, it would be designated as an F4 according to his scale. Fujita characterized the impact of F4 tornadoes as follows: “Entire frame houses flattened, resulting in piles of rubble; significant damage to steel structures; trees stripped of bark by small airborne debris; vehicles and trains thrown or rolled considerable distances; and large projectiles created.”

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The F Scale rapidly influenced the meteorology field, and a modified version of the scale is still utilized today to classify all tornadoes in the United States.
This system allows meteorologists to accurately assess the strength and potential damage of tornadoes, providing crucial information for warning and preparedness efforts. The F Scale has become an essential tool in understanding and predicting the impact of tornadoes, helping to save countless lives and minimize destruction. Its legacy continues to shape the field of meteorology and improve our ability to mitigate the devastating effects of these powerful natural phenomena.

Pronunciation of the Fujita Scale

Before we dive into the details, let’s address the pronunciation of the Fujita scale. Think of Mount Fuji, the highest mountain in Japan. With that in mind, the IPA pronunciation of the Fujita scale would be “fuˈʤitə skeɪl”.

Fujita Scale
The original Fujita Scale for damaging winds Credits: University of Chicago

Fujita Scale Definition

The Fujita scale is a measurement system used to determine the strength and impact of a tornado on man-made structures and vegetation in affected areas. Created in the 1970s by Dr. Ted Fujita, this scale consists of five main grades (F1-F5) that allow meteorologists to categorize tornadoes based on their destructive potential.

To predict a tornado’s destructive capabilities, meteorologists utilize various techniques such as weather radars, satellite imagery, historical meteorological data, ground-swirl patterns, and analysis of the area’s landscape. They also draw on their past experiences with similar tornadoes when categorizing a current event.

After the occurrence of a tornado, meteorologists rely on reports from the media and eyewitnesses to gather data for determining the appropriate Fujita scale category (F1-F5) of the tornado.

Now, let’s explore each category of the Fujita scale in more detail:

F0 Tornado

An F0 tornado refers to a tornado that causes little to no damage. These tornadoes have minimal impact on human-built structures and natural surroundings.

F1 Tornado

F1 tornadoes can cause moderate damage to human-built objects and natural environments. Examples of F1 tornado damage include vehicles being pushed off the road and surface peeling off roofs. The wind speeds associated with F1 tornadoes range from 73 to 112 miles per hour, and their diameter typically falls between 6 and 17 yards.

F2 Tornado

F2 tornadoes can cause significant damage. They have the capability to push over cars and mobile homes, as well as break large trees in half. The wind speeds of F2 tornadoes, as per the Fujita tornado damage scale, range from 113 to 157 miles per hour, while their path width typically spans from 56 to 175 yards.

F3 Tornado

Rated as F3 by the Fujita scale of tornado intensity, tornadoes can cause severe damage to property and vegetation. These tornadoes can tear off walls and roofs, overturn cars and trains, and inflict extensive destruction. F3 tornadoes have wind speeds ranging from 158 to 206 miles per hour, and their diameter falls between 176 and 566 yards.

F4 Tornado

F4 tornadoes can cause devastating damage to property. As per the Fujita tornado damage scale, they have the power to break down houses and lift cars off the ground. Due to their strength, F4 tornadoes, rated on the Fujita tornado scale, often result in significant fatalities. The wind speeds associated with F4 tornadoes, as characterized by the Fujita tornado scale, range from 207 to 260 miles per hour, and their diameter typically ranges from 0.3 to 0.9 miles.

F5 Tornado

The highest grade on the Fujita scale is the F5 tornado. These tornadoes cause incredible damage to property and vegetation, often resulting in a high death toll. F5 tornadoes can lift homes from their foundations and carry cars several miles away. The wind speeds characterizing F5 tornadoes range from 261 to 318 miles per hour, and the diameter of their path can span from 1.0 to 3.1 miles.

Fujita Scale Rating
Credit: KYTX

Understanding the different tornado intensity levels

Each level of the Fujita tornado damage scale represents a distinct range of wind speeds and associated damage, providing valuable insights into potential tornado projects. An F0 tornado, the weakest on the scale, typically exhibits wind speeds of 65-85 mph and causes minimal damage, such as breaking tree limbs and damaging chimneys. As the scale progresses, the intensity increases, with F1 tornadoes reaching wind speeds of 86-110 mph and causing moderate damage to roofs and exterior walls. F2 tornadoes on the Fujita tornado scale, with wind speeds of 111-135 mph, can result in considerable damage, including roofs being lifted off the ground and mobile homes being overturned.

F3 tornadoes, with wind speeds of 136-165 mph, cause severe damage, such as the collapse of well-constructed houses and the uprooting of large trees. F4 tornadoes, with wind speeds of 166-200 mph, lead to devastating damage, including the leveling of strong-framed houses and the displacement of cars and other heavy objects. The highest level, F5 tornadoes, with wind speeds exceeding 200 mph, bring catastrophic destruction, such as the sweeping away of entire houses and the debarking of trees. Understanding these different levels is essential for assessing the potential impact of tornadoes and preparing for their effects.

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Examples of tornadoes at different Fujita Scale levels

To illustrate the varying intensity levels of tornadoes, it is informative to examine historical examples of tornadoes that have been categorized according to the Fujita Scale. For instance, the 1999 Bridge Creek-Moore tornado in Oklahoma was classified as an F5 tornado, showcasing the extreme devastation and winds exceeding 260 mph.

This tornado resulted in widespread destruction, including the complete destruction of numerous homes and buildings, and sadly, significant loss of life. In contrast, the 2008 EF2 tornado in Atlanta, Georgia, demonstrated the impact of a less intense tornado, with wind speeds of 111-135 mph causing damage to roofs and trees, but with no reported fatalities. These real-world examples highlight the significance of accurately assessing tornado intensity and its correlation with the resulting impact on communities and infrastructure.

The impact of tornado intensity on communities

The intensity of tornadoes has a profound impact on communities, influencing the level of destruction, the potential for injuries and fatalities, and the long-term recovery process. Tornadoes with higher Fujita Scale ratings, such as F4 and F5, can cause widespread devastation, leading to significant property damage and loss of life.

These intense tornadoes can also disrupt critical infrastructure, including power lines, water supplies, and transportation networks, exacerbating the challenges faced by affected communities. In contrast, tornadoes with lower ratings, such as F0 and F1, typically result in less severe damage, but can still pose risks to individuals and property. Understanding the impact of tornado intensity on communities is essential for developing effective emergency response plans, implementing mitigation strategies, and enhancing overall resilience to these natural disasters.

tornado intensity on communities

Safety measures based on Fujita Scale ratings

The Fujita Scale provides valuable guidance for implementing safety measures based on the anticipated intensity of tornadoes. For areas at risk of tornadoes, it is essential to have a comprehensive emergency plan in place, including designated shelter areas and clear communication protocols. Communities located in regions prone to severe tornadoes should prioritize the construction of tornado-resistant structures and the implementation of early warning systems to alert residents of impending storms. Additionally, residents should be educated on the importance of seeking shelter in interior rooms or underground spaces during tornadoes, especially when facing higher intensity storms. By aligning safety measures with Fujita Scale ratings, communities can enhance their preparedness and minimize the potential impact of tornadoes on lives and property.

Is There an F6 Tornado Category?

The existence of F6 tornadoes is a topic of debate in the meteorological community, even on the new scale based on the Fujita tornado damage scale. While no F6 tornadoes have occurred to date, if they were to happen, F6 tornadoes would cause unimaginable damage. They would turn cars and other objects into missiles, lifting them high into the air and moving them at super-high speeds for miles.

Introduction of the Enhanced Fujita Scale (EF-Scale)

The Fujita scale served as the official tornado measurement scale in the United States from 1971 to 2007, when it was replaced by the Enhanced Fujita Scale (EF-Scale). The EF-Scale is an advanced version of the original Fujita scale and is currently used in both the United States and Canada.

The EF-Scale retains the foundation of the original Fujita scale but incorporates significant differences. One major difference is that the EF-Scale considers the quality of construction of man-made buildings. This adjustment on the Fujita tornado damage scale acknowledges that some structures are more resistant to tornado winds than others.

Another difference lies in the wind speed classification, particularly within the F5 category. The original Fujita scale classified F5 tornadoes as those with wind speeds ranging from 261 to 318 miles per hour. In contrast, the EF-Scale designates all tornadoes with wind speeds above 200 miles per hour as EF5 tornadoes.

The future of tornado intensity measurement

As technology and scientific understanding continue to advance, the measurement of tornado intensity is poised to undergo further enhancements and refinements. Researchers are exploring innovative methods, including the use of remote sensing technologies and advanced modeling techniques, to improve the accuracy of assessing tornado intensity. Additionally, the integration of real-time data from weather satellites and ground-based sensors offers the potential for more precise and timely evaluations of tornado strength.

These developments hold the promise of providing more detailed and actionable information for forecasting tornadoes and informing emergency response efforts. By embracing the Fujita tornado scale and other advancements, the future of tornado intensity measurement aims to further empower communities and authorities to effectively prepare for and respond to these natural phenomena.

Example of an EF5 Tornado

A notable example of an EF5 tornado on the Fujita tornado scale is the one that struck Chapman, Kansas in 2016. This tornado lasted for over four days and caused extensive damage throughout the area. It flipped over cars, buses, and heavy machinery, leveled houses, and uprooted numerous trees. Fortunately, there were no fatalities, thanks to the timely warnings issued by meteorological services to the residents of Chapman.

EF5 tornadoes, as per the EF Scale, are the most destructive tornadoes with winds exceeding 200 miles per hour. They are capable of causing severe damage or total destruction to large structures, and have the strength to crush or carry large vehicles over long distances.

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The most devastating impact often arises when objects, such as trees and cars, are lifted off the ground and become airborne projectiles, a phenomena often associated with tornadoes by the Fujita tornado scale. The deadliest tornado in U.S. history, the “Tri-State Tornado” of March 18, 1925, was an EF5 tornado that claimed 695 lives and left a trail of destruction spanning Missouri, Illinois, and Indiana, covering a record 219 miles and causing an estimated 15,000 homes to be destroyed.

In 2022, the latest documented EF5 tornado was observed in Moore, Oklahoma, on May 20, 2013. It remained active for approximately 40 minutes and expanded to a width of one mile at certain points, resulting in extensive destruction, including damage to multiple elementary schools, and claiming 25 lives. Following the introduction of the F Scale, meteorologists discovered that F3, F4, and F5 tornadoes constitute only around 9 to 12 percent of all tornadoes, yet they are responsible for 88 percent of tornado-related fatalities.

This realization has led to a greater focus on early warning systems and public education for severe weather preparedness, with the goal of reducing the impact of these catastrophic events. Additionally, advancements in technology have allowed for more accurate and timely tornado warnings, giving people more time to seek shelter and potentially saving lives. Despite the devastating power of EF5 tornadoes, efforts to improve forecasting and preparedness continue to progress in hopes of minimizing their destructive effects.

FAQS

Q: What is the Fujita Scale and the Enhanced Fujita Scale?

A: The Fujita Scale and the Enhanced Fujita Scale are measures used to categorize tornado damage, with the latter being an improved and updated version of the former.

Q: How do the Fujita and Enhanced Fujita Scales assess tornado damage?

A: Both scales assess tornado damage based on the degree of damage to various structures and objects, such as houses, trees, and signs, as well as the estimated wind speeds corresponding to each level of damage.

Q: What are the main differences between the Fujita Scale and the Enhanced Fujita Scale?

A: The main differences include the incorporation of more specific damage indicators, updated wind estimates, and refined damage categories in the Enhanced Fujita Scale compared to the original Fujita Scale.

Q: Why was the Enhanced Fujita Scale developed?

A: The Enhanced Fujita Scale was developed to provide better examinations of tornado damage and improve tornado intensity estimation, leading to more accurate assessments of tornado strength and wind speeds.

Q: Who developed the Fujita Scale?

A: The Fujita Scale was developed in 1971 by Dr. Ted Fujita of the University of Chicago in collaboration with the National Oceanic and Atmospheric Administration (NOAA).

Q: What are some examples of damage indicators used in the Fujita and Enhanced Fujita Scales?

A: Examples of damage indicators include damage to chimneys, large trees snapped or uprooted, trees debarked, and structural damage to buildings.

Q: How are tornado damage surveys and the Fujita Scales connected?

A: Tornado damage surveys are used to assess the damage caused by tornadoes and provide data for determining the appropriate Fujita or Enhanced Fujita scale rating for the tornado.

Q: What organizations use the Fujita and Enhanced Fujita Scales for rating tornado damage?

A: The National Weather Service (NWS) and the Storm Prediction Center (SPC) use the Fujita and Enhanced Fujita Scales as part of their assessment and rating of tornado damage.

Q: Can the Fujita and Enhanced Fujita Scales provide accurate estimates of actual wind speeds in tornadoes?

A: While the Fujita and Enhanced Fujita Scales provide estimated wind speeds based on damage indicators, they do not provide direct measurements of actual wind speeds in tornadoes.

Q: What is the significance of the Fujita and Enhanced Fujita Scales in tornado research and analysis?

A: The Fujita and Enhanced Fujita Scales play a crucial role in tornado research, analysis, and maintaining a tornado database, providing valuable insights into tornado intensity and the destructive potential of tornadoes.

Conclusion

In conclusion, the Fujita Scale, also known as the Fujita tornado scale, serves as a critical tool for understanding tornado intensity levels and assessing their potential damage. Through its historical evolution and ongoing refinements, this scale has provided valuable insights into the strength of tornadoes and has informed safety measures and emergency planning.

By comprehending the different levels of the Fujita Scale and their associated damage and wind speeds, individuals and communities can make informed decisions to mitigate the impact of tornadoes. As technology and research continue to progress, the measurement of tornado intensity is poised to become even more precise, offering enhanced capabilities for forecasting and responding to tornadoes. By decoding the Fujita Scale, society can enhance its resilience to these powerful natural phenomena and reduce the risks posed by tornadoes.

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