For almost 40 years, it was simply called the Super Outbreak -- a weather event, up until that time, that had never occurred with such magnitude.

On April 3 and 4, 1974, forty-five years ago today, a powerful storm system made its way across the United States and into the Ohio and Tennessee Valleys. The system produced widespread severe thunderstorms and some of those strongest storms produced tornadoes.

In a period of less than 24 hours, the system produced 148 confirmed tornadoes. The first tornado occurred in northern Illinois and was a short lived system. Other, more powerful tornadoes continued to form into the afternoon and evening hours of April 3.

One of the hardest hit towns was Xenia, Ohio. A devastating F5 tornado destroyed a large portion of the town and caused 32 fatalities. Other significant tornado damage occurred in Brandenburg, Kentucky, where 31 deaths were reported.

In all, the storms caused 315 fatalities along with 5,484 injuries. Damages estimates were more than $600 million. That's $3.3 billion in today's currency.

When the storm surveys were completed, seven tornadoes were rated as F5. Twenty-three were rated as F4 and 35 were rated at F3 strength.

The final two tornadoes of the outbreak occurred in North Carolina on the morning of April 4. The 148th and final tornado of the outbreak, was reported in Caldwell County in the North Carolina foothills.

In April 2011, the term "Super Outbreak" was no longer used to identify this severe weather event. On April 25-28, 2011, a weather system produced 360 tornadoes in a three-day period. This occurred less than two weeks after the April 16, 2011 tornado outbreak that impacted central and eastern North Carolina.

As of April 2011, the Super Outbreak is now referred to as the "1974 Super Outbreak".