Tornado is a localized, violently destructive windstorm occurring over land, especially in the Middle West, and characterized by a long, funnel-shaped cloud extending toward the ground and made visible by condensation and debris. Various types of tornadoes include the land spout, multiple vortex tornado, and waterspout. Waterspouts are characterized by a spiraling funnel- shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-super cellular tornadoes that develop over bodies of water.
Tornadoes form in unusually violent thunderstorms when there is sufficient instability and wind shear present in the lower atmosphere. Instability refers to unusually warm and humid conditions in the lower atmosphere, and possibly cooler than usual conditions in the upper atmosphere. Wind shear in this case refers to the wind direction changing, and the wind speed increasing, with height. An example would be a southerly wind of 15 mph at the surface, changing to a southwesterly or westerly wind of 50 mph at 5,000 feet altitude. The
intense spinning of a tornado is partly the result of the updrafts and downdrafts in the thunderstorm.
Some steps can be taken to protect from their destruction, but sometimes tornadoes are so powerful that even these steps can be ineffective. These are usually huge F5 tornadoes, and, thankfully, they are rare. Open the windows of houses to equalize pressure within the house. Basements or tornado cellars are the best shelters in case of tornado.