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North American Tornado Swarm 1974

North American Tornado Swarm 1974

What Caused the 1974 Super Tornado Outbreak

On April 1st 1974, a very intense low pressure system formed on the plains of the US and started to move eastward towards the Mississippi and Ohio Valleys.

It collided with a large mass of moist air and caused extreme differences in temperature. This spun off several tornadoes in these areas and in parts of the Southern US on April 1st and 2nd.

On April 3rd, the storm area spread to the Great Lakes region and severe weather watches were issued. By early afternoon the Super Outbreak began!

Events of the 1974 Super Tornado Outbreak

In Illinois and Indiana, several groups of thunderstorms and supercells (which cause tornadoes) began to form. These intense storms moved towards the Ohio Valley and in the late afternoon, it spawned four F5 tornadoes between 4:30pm to 6:30pm on April 4th 1974. This was due to three supercells which hit central and southern Ohio, southern Indiana and northern Kentucky. Some of these areas had already experienced tornadoes on April 1st and 2nd.

At the same time, thunderstorms developed in an area which spread from the Appalachians to Georgia. On the evening of April 3rd, storm activity in the south began to escalate. Several tornadoes hit central Tennessee, eastern Kentucky and northern Alabama.
Meanwhile in the north, more supercells developed over southern Michigan and northern Indiana. Additional tornadoes touched down, including Windsor Ontario, between 6:00pm and 10:00pm.

On the morning of April 4th, the southern storm moved up towards the Appalachians and generated several tornadoes in the southeastern states.

By the end of April 4th 1974, the Super Outbreak produced 148 twisters.

Interesting Facts About the 1974 Super Tornado Outbreak

On the Fujita Scale, the following is a breakdown of the intensities and the number of tornadoes recorded during the Super Outbreak:

F5 – 6
F4 – 24
F3 – 34
F2 – 32
F1 – 33
F0 – 19

The F5 Tornadoes struck the following locations:

Xenia Ohio
Cincinnati Ohio
Brandenburg Kentucky
Harvest Alabama (also had a F4 later on in the day)
Guin Alabama
DePauw Indiana

States/Provinces Affected – Illinois, Indiana, Michigan, Ohio, Kentucky, Tennessee, Alabama, Mississippi, Georgia, North Carolina, Virginia, West Virginia, New York and Ontario Canada.

Duration of the Super Outbreak – 18 hours
Death Toll – 330 people
Number of People Injured – over 6,000
Estimated Property Damage – $600 million
Total Area of Destruction – 900 square miles
Total Combined Path – 2600 miles
Number of Tornadoes with Paths over a Mile Long – 118
Number of Tornadoes on the Ground at the Same Time – 15

Detecting and Predicting Tornadoes

In 1974, the National Weather Service was still using radar to detect weather patterns. Weather warnings were sent to TV and Radio stations through a teletype machine which had to be manually fed by an operator. During the Super Outbreak, the changes to the weather systems were too frequent to keep up to date.

Today’s technology uses Doppler radar for tracking storms which is responsive and more accurate. Communication is now done through more efficient electronic means. As weather prediction becomes quicker, this allows more lead time for residents to make preparations for impending disaster.

Xenia Ohio Tornado April 1974

A low-pressure system that developed on the Great Plains became more intense when it collided with moist air in the Mississippi and Ohio Valleys. During April 1st and 2nd, 1974, thunderstorms and tornadoes hit Tennessee, Kentucky and Alabama.

By April 3rd, 1974, severe weather watches were issued as the storm activity continued and spread into the Great Lakes region. A second weather front developed further south in northern Georgia, southern Alabama and eastern Tennessee.

The more intense northern storm front struck Xenia, Ohio and produced four additional F5 tornadoes in a span of two hours. Other F5 tornadoes struck Indiana, Kentucky, and Alabama.

The 1974 Super Outbreak was described in This Day in History. “… 148 tornadoes hit the United States heartland within 16 hours. By the time the deadly storm ended, 330 people had died. This was the largest grouping of tornadoes recorded in its time, affecting 11 states and Ontario, Canada. At any one moment, there were as many as 15 separate tornadoes touching the ground. “

Formation of the Xenia Ohio Tornado

The F5 tornado that struck Xenia, Ohio was the deadliest single twister in the Super Outbreak in 1974. It was the third F5 tornado on April 3, 1974. The tornado formed nine miles southwest of Xenia and intensified as it moved northeast. In the beginning, two funnels were spotted and then merged into a large wedge-shaped funnel.

Ten minutes later, the funnel reached Xenia at 4:40 pm. By the time the tornado struck Xenia, winds were clocked at 260 miles per hour. The funnel spanned approximately one-half mile and stayed on the ground for nine minutes, which is double the time the average tornado stays on the ground.

The residents of Xenia were taken by surprise because there were no warning sirens installed.

Damage Caused by the Xenia Ohio Tornado

The tornado first struck two subdivisions near Route 68. Homes were blown away or reduced to rubble in the Windsor Park and Arrowhead neighborhoods. The tornado proceeded to the downtown business area where it flattened churches, schools, businesses, and apartment buildings. The tornado then hit the Pinecrest Garden district, situated in the northeast section of Xenia.

People were injured or killed by flying debris and collapsed buildings. Two National Guard members died in a fire that erupted in makeshift barracks. A freight train traveling through Xenia had several cars lifted and blown over.

Xenia High School was flattened and it would have been worse if the tornado had struck when school was in session. In the end, the tornado leveled over half of Xenia and thousands of people were injured.

According to USA Today, “The storm leveled all but a handful of 400 new ranch-style homes. It flattened century-old buildings, shredding like paper dollhouses the graceful Victorians and the brick storefronts along Detroit Street downtown. Nine churches, four schools and 1,333 homes and businesses were destroyed. In all, 33 people died in Xenia’s tornado.”

On September 20, 2000, a F4 tornado struck Xenia. More than 300 homes and 30 businesses were destroyed or damaged. One person was killed. With advances in weather prediction and warnings since 1974, the number of casualties was significantly reduced.