A tornado, a localized and very destructive windstorm that occurs over land, is also referred to as a cyclone, twister or funnel. These funnel-shaped appendages stretch from a storm cloud to the ground and consist of wind rotating very fast in a circular motion.
The rotating wind within a tornado catches debris, such as dirt and rocks, or larger things, such as buildings and cars, as it travels across land. This debris is what makes the tornado visible. All tornadoes are considered dangerous, but stronger ones can become deadly.
Rotation begins when two streams of wind, both at different altitudes and moving in opposite directions, create wind shear. This causes a horizontal rotation of wind. When this horizontal column of spinning wind gets caught in a supercell updraft, the column becomes vertical and is known as a funnel. If the funnel touches ground, it becomes a tornado.
On April 27, 2011, the United States experienced the largest tornado outbreak on record. The southern states of the country was hit with numerous F5 tornadoes, which is the strongest category. A total of 62 tornadoes hit Alabama alone that day. The total death count from the April 27, 2011, outbreak was 316 deaths.