Date: May 3, 1999
Fujita scale intensity: F3-F5
Injured: More than 775
On May 3, 1999, meteorologists were on alert.
The conditions were perfect for severe weather in the states of Tornado Alley. Cold air from the west was clashing with warm, moist air to the east. Large thunderstorms were likely, and tornadoes were a definite possibility.
The National Weather Service called in extra staff to monitor the situation. The early warnings that resulted are credited for saving manyperhaps more than 700lives.
In all, five states, from Texas to South Dakota, saw tornadoes that day. But none were as violent as the ones that ripped through Oklahoma.
At least 45 tornadoes touched down in the Sooner State, including an immense F5 twister that traveled about 38 miles (61 kilometers) and ravaged Oklahoma City suburbs.
The F5 tornado developed near the town of Amber and quickly grew to nearly three-quarters of a mile (1.2 kilometers) wide. By the time the tornado reached Bridge Creek, it had widened into a monstrous 1-mile (1.6-kilometer) vortex.
The tornado peeled 1 inch (2.5 centimeters) of asphalt pavement from a rural road and wrapped roofing material neatly around power lines. In one subdivision, more than 200 homes were wiped clean from their foundations. The bark was stripped from cedar trees. All vegetation was torn away, leaving mud and red dirt exposed.
NASA scientists, studying the area with satellites, estimate it will take anywhere from 10 to 20 years for the vegetation in tornado-ravaged areas to grow back. In some areas the tornado picked up nearly a foot (0.3 meter) of topsoil, stripping the earth of nutrients.
The tornado generated about 2 million cubic yards (1.5 million cubic meters) of debris and waste in just a few hours. That's as much as Oklahoma City would normally create in an entire year.
So many structures were ripped to shreds that the air smelled like sawdust, witnesses said.
Experts stressed that the death toll from the tornado could have been much higher, had it not been for the early warnings from storm spotters and meteorologists.