Tornadoes

The tornado is a violent column of rotating air that is moving between 70 and 200 kilometer per hour. Some winds as high as 450 kph have been recorded. They come in many sizes from less than 100 meters across to 2 kilometers across and some stay on the ground for less than a minute while others can stay on the ground and travel for 100 kms.

In April 1974, southern and mid-western US suffered its worst tornado episode. Over a 24-hour period, 148 swept through the region. Thirteen states from Alabama to Virginia were affected. After 16 hours, 330 people were dead and 5,484 were injured in a damage path covering more than 2,500 miles. Tornadoes form during thunder storms when warm, humid air collides with colder air to form a swirling vortex.

This pictures shows a big tornado just getting started.