Tornado conditions are caused when different temperatures and humidity meet to form thunderclouds.When this occurs, the cold air on top begins to sink, sending the rising warm wind spinning upward. The warm winds rotate faster and faster in a high column. When the updraft is strong, the column can rise to heights of 10 miles or more, twisting at speeds of up to 100 miles an hour.
Wall clouds are large, localized, persistently lowering clouds that look like they almost for a wall on the horizon. A funnel cloud is a cloud formed with condensation and water droplets and rotating winds that drop from the base of the clouds.
Tornado alley is a part of the US where tornadoes usually occur it includes parts of Texas, Oklahoma, South Dakota, Nebraska, Colorado, Kansas, Wyoming, Iowa, and Minnesota.
The most destructive tornado is the Tri-State tornado that made a 200 mile track through Missouri, Indiana, and Illinois. It was an F5 and the most destructive tornado in the history of the US.
Tornado season is usually from March to May in southern states. The reason for this is that low-level heat, moisture, and instability necessary for tornado formation are usually confined to southern regions early in the year, and only reach northern sections with regularity late in the spring.