What The 1974 Super Outbreak Taught Us About Tornadoes And Forecasting

Fifty years ago, the April 3-4, 1974, super outbreak tore through the Ohio Valley, South and Great Lakes, but also accelerated the development of our tornado warning system we heavily rely on today.

The S​taggering Stats

This occupies a spot on the Mount Rushmore of U.S. historical weather events as one of the worst tornado outbreaks in U.S. history.

In 24 hours, 148 tornadoes tore through parts of 13 states and Ontario, Canada.

Thirty were violent tornadoes, rated at least F4. Six of the violent tornadoes were F5, the most intense tornadoes in the Fujita – now Enhanced Fujita – scale. A typical year only has eight to nine such violent tornadoes.

Forty-eight of those 148 tornadoes were deadly, claiming 335 lives, with over 6,000 injured.

The total path length of all those tornadoes was a jaw-dropping 2,521 miles, roughly the distance between New York City and Las Vegas. The total damage was estimated to be $1.5 billion.

At one time, 15 tornadoes were simultaneously in progress. Many of those tornadoes moved at forward speeds of 50 mph or more.

Among the hardest-hit cities were Xenia, Ohio (34 killed); Monticello, Indiana; Brandenburg, Kentucky (28 killed); and Guin, Alabama. Birmingham; Cincinnati; Louisville; and Windsor, Ontario, were among the metro areas hit.

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After this super outbreak, several important advances in both science and public awareness of severe weather were spurred. Some took two decades to fully implement; others were phased in faster.

Here are eight things we may take for granted today that were not in place during the 1974 super outbreak.

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1. Our Radar Network Was Sorely Inadequate

Today, there is a nationwide network of National Weather Service Doppler radars, and many local television stations also have their own.

In 1974, Doppler radar was only in development in the research community. Radar available to operational meteorology was crude by modern standards.

"The radar was very manually intensive, and took a lot of experience for correct storm interpretation," said Allan Fisher, who was a meteorologist at the NWS in Chicago at the time.

Lacking Doppler radar's capability to measure the motion of rain, hail and snow relative to the radar site, meteorologists couldn't diagnose developing rotation in thunderstorms, occasionally a precursor for tornadogenesis. The 1974 super outbreak gave a boost in urgency for Doppler radar research and development.

While it took another two decades, Doppler radars gradually replaced the aging WSR-74 (for 1974) and WSR-57 (for 1957) radars in the 1990s.

2. We Needed More Warning Lead Time

In the pre-Doppler era, forecasters in 1974 were often unable to issue tornado warnings simply based on examining the splotches on their radar. Until visual confirmation of a tornado was received, a warning was typically not issued.

Today, while only a small fraction of rotating thunderstorms produce tornadoes, lead time for tornado warnings ranges from 8 to 15 minutes. In some cases where a long-track supercell repeatedly spawns tornadoes, the lead time can be up to 30 minutes.

3. We Needed To Receive Warnings Instantly

In 1974, tornado warnings were disseminated using a teletype system in which warnings had to be punched into a paper tape, then manually fed through a reader.

With multiple tornadoes in progress at one time on April 3, 1974, there was a bottleneck. Some warnings weren't transmitted until an hour after the original issuance time.

A faster weather wire was implemented soon after the super outbreak, and warnings were properly prioritized over other NWS products.

Today, we can receive warnings via television, social media, NWS Wireless Emergency Alerts or smartphone apps the instant they are issued.

4. NOAA's Weather Radio Network Had To Expand

Given the bottleneck of transmitting numerous warnings via teletype during the super outbreak, the NWS knew it needed a better way to get a warning directly to the public.

The NOAA Weather Radio network expanded from only 50 to 60 stations mostly in large cities near the coasts to 330 more. That network would grow to cover 95% of the nation's population after the Palm Sunday 1994 tornado outbreak.

Today, there are over 1,000 transmitters covering all 50 states, coastal waters, Puerto Rico, the U.S. Virgin Islands and Pacific territories.

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5. Better School Safety Awareness Needed

Although they were done in many tornado-prone states like Kansas and Oklahoma, some schools hit during the super outbreak had never conducted a tornado drill.

The town of Monticello, Indiana, lost three schools to one tornado. Twenty-four schools were damaged in Indiana alone, according to former NWS Central Region Director Richard Augulis. Seven of the 12 schools in Xenia, Ohio, were hit by the outbreak.

"Evidence from the damaged buildings supported the claim that inside hallways provide the safest place and that classrooms with outside walls and gymnasiums with wide roof spans are the most dangerous places for students at school during severe weather," said Augulis.

6. Tornado Myths Were Debunked

The super outbreak delivered the final blow to several long-standing myths.

First, based on damage surveys, meteorologists proved that buildings do not explode due to pressure differences as the tornado passes through. Therefore, wasting precious seconds opening windows to equalize pressure won't do any good.

Other debunked myths involved tornadoes overcoming terrain.

The Guin, Alabama, tornado climbed, then descended 1,640-foot Monte Sano Mountain, intensifying as it descended. So much for hills or mountains weakening a tornado.

The belief of rivers somehow mitigating tornadoes was also blown apart by the Sayler Park, Ohio, F5 tornado, which crossed the Ohio River.

7. A Blueprint For More Routine Storm Surveys

While damage surveys had been conducted before, the super outbreak presented an opportunity to conduct the largest, most comprehensive storm survey up to that point.

Starting from initial reports from the National Severe Storms Forecast Center – now called the Storm Prediction Center – and local newspapers, famed tornado researcher Dr. Theodore Fujita and his group from the University of Chicago investigated every tornado track over more than three months. This group included now-retired former severe weather expert Dr. Greg Forbes of The Weather Channel.

In April 1974 alone, Fujita logged over 13,000 flight miles in his Cessna as he conducted aerial surveys, Forbes previously told weather.com.

The aerial surveys also found starburst-shaped damage patterns that were later connected to downburst winds, a discovery that led to major improvements in aviation safety.

Today, storm surveys can sometimes be conducted in a few hours by a team from the local NWS office. Frequently, photos and reports during the survey itself are sent via each NWS office's social media accounts. Drones provide valuable footage in areas that are not accessible by foot or vehicle.

We also now have an Enhanced Fujita scale rolled out in 2007 with more damage indicators, allowing storm survey crews to give better estimates of tornado wind speeds.

Dr. Fujita's landmark survey of the 1974 super outbreak set the standard.

8. A Severe Weather Expert Almost Turned Tropical

Dr. Greg Forbes, hurricane expert. If not for the super outbreak, that could have happened.

Forbes was a graduate student at the University of Chicago studying under Fujita in early 1974.

"Dr. Fujita was running out of research funds to support my studies," Forbes told weather.com. "I was literally in an interview to possibly get funding that would have had me studying the formation of tropical storms off the coast of Africa when a hailstorm came over our building."

Just after the super outbreak, Forbes was told by Fujita his funding would be renewed.

"My doctoral studies were primarily supported by the U.S. Nuclear Regulatory Commission, who wanted to know more about tornado intensity and characteristics in order to ensure reactor safety," Forbes said.

That twist of fate kept Forbes on a path that would eventually lead him to be the severe weather expert at The Weather Channel from 1999 until his retirement in 2017.

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Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter with a tornado as a child in Wisconsin. He studied physics at the University of Wisconsin-Madison, then completed his Master's degree working with dual-polarization radar and lightning data at Colorado State University. Extreme and bizarre weather are his favorite topics. Reach out to him on X (formerly Twitter), Threads, Facebook and Bluesky.