A tornado is a violent and rapidly rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud (thunderstorm cloud). Tornadoes can vary in size, strength, and duration. They typically form from powerful thunderstorms known as supercells, which have specific atmospheric conditions conducive to tornado formation.
The process of tornado formation begins with the development of a rotating updraft within a thunderstorm. This rotation is often initiated by the presence of wind shear, which is a change in wind speed and/or direction with height. When the updraft and the rotating air align, a mesocyclone is formed.
Within the mesocyclone, the updraft intensifies, drawing in more warm, moist air from the surroundings. This creates a region of intense rotation known as the tornado vortex. As the vortex tightens and descends from the base of the storm, it becomes visible as a funnel cloud. If the funnel cloud makes contact with the ground, it is then officially classified as a tornado.
The wind speeds within a tornado can vary widely, ranging from relatively weak tornadoes with speeds of around 65 mph (105 km/h) to the most extreme tornadoes with wind speeds exceeding 300 mph (480 km/h). The Enhanced Fujita (EF) scale is commonly used to categorize tornadoes based on their estimated wind speeds and associated damage. This scale ranges from EF0 (weakest) to EF5 (most powerful).
When it comes to the wind speed at the time of landfall, it depends on various factors, including the strength and size of the tornado, the terrain, and the surrounding atmospheric conditions. The wind speeds can be highly localized and vary within the tornado's path. It is essential to note that tornadoes can cause extensive damage and pose severe risks to life and property, regardless of the exact wind speed at landfall. It is crucial to follow the guidance and warnings provided by local meteorological authorities and seek appropriate shelter during tornado events.