The 1970 Lubbock tornado led to the Fujita scale. Then, Texas Tech created the EF-scale

Yahoo

11-05-2025

On the morning of May 11, 1970, skies darkened over Lubbock and winds began to rise, setting the stage for the kind of storm many in Tornado Alley pray never comes their way.
By late that Monday evening, dozens of tornadoes had touched down across the Great Plains and Midwest. In Lubbock, two tornadoes struck that evening: the first, relatively small, around 8:45 p.m., roughly an hour before, as described by the National Weather Service, 'the most massive tornado touched down over the heart of the city of Lubbock."
As it tore through downtown — then a bustling hub of commerce and daily life — the Lubbock tornado killed 26 people, injured more than 1,500, and caused over $100 million in damage. The destruction was so severe that it led meteorologists to rethink how tornadoes were measured, ultimately resulting in the creation of the Fujita Scale one year later, which rates tornadoes by intensity and damage.
Its destruction was so extreme that Tetsuya Theodore Fujita, the University of Chicago professor who developed the tornado intensity scale, gave it one of only two experimental F6 ratings ever considered. His analysis of the Lubbock storm became, as researcher Thomas P. Grazulis described, 'the most detailed mapping ever done, up to that time, of the path of a single tornado.'
But it was later downgraded to F5, as the scale was never intended to exceed that limit, and remains only one of six to ever touch down in the Lone Star State in recorded history.
Over the years, as tornado science advanced and the understanding of tornadoes and their damage improved, limitations in the original Fujita Scale became apparent to meteorologists and forecasters. Decades after the Lubbock storm, researchers at Texas Tech University played a key role in developing the more accurate Enhanced Fujita (EF) Scale.
"NWS personnel, who are responsible for rating tornadoes, have expressed frustrations in applying the Fujita Scale in a consistent and accurate manner," faculty from the Wind Science and Engineering Center wrote in their proposal. "Weak links in a structural system or a slow-moving storm sometimes lead to an over rating of a tornado event."
Tornadoes are measured on the EF Scale, which replaced the Fujita Scale in 2007.
The scale measures wind speeds of tornadoes by looking at the damage caused on the ground after it has dissipated. They are ranked from EF0 to EF5.
EF0 - light damage with wind speeds of 65-85 mph.
EF1 - moderate damage with winds of 86-110 mph.
EF2 - considerable damage with winds of 111-135 mph.
EF3 - severe damage with winds of 136-165 mph.
EF4 - devastating damage with 166-200 mph.
EF5 - With winds of over 200+ mph, they are the most devastating tornadoes on the scale.
A recent addition to the scale is an EFU tornado — an unidentifiable tornado. The National Weather Service classification is given when it knows there's a tornado, but there's not always a lot of damage to classify it.
Damage Indicators
Fujita Scale: This scale rates tornadoes based on the damage they cause to structures like buildings, trees, and other objects. However, it used general damage indicators, focusing on the level of destruction without taking into account the specifics of building construction or more detailed factors.
Enhanced Fujita Scale: The EF Scale refines those damage indicators by considering the quality of the structures affected. It differentiates between types of buildings, such as weak versus well-built houses, and uses a broader set of damage indicators, which allows meteorologists to assess wind speeds more accurately.
Wind Speed Limits
Fujita (F) Scale: The F Scale was based on observed damage, with wind speeds estimated indirectly, using the severity of destruction as a guide. This method was criticized for being too generalized, especially when differentiating between tornadoes with similar intensity but different damage types. The scale also lacked the precision needed to account for environmental factors like terrain or building quality.
Enhanced Fujita (EF) Scale: The EF Scale was developed to improve tornado intensity ratings by providing a more accurate estimate of wind speeds. It assigns a range of wind speeds for each category (EF0 to EF5) and uses detailed damage indicators, like distinguishing between damage to well-built houses versus mobile homes, allowing for more precise wind speed estimates based on specific damage observations.
This article originally appeared on Austin American-Statesman: What is the EF-scale for tornadoes? Why Texas Tech created a new one