How are tornadoes formed?
Tornadoes are rotating columns of air that is in contact with the ground. The catalyst that lead to tornadoes are temperature and humidity instability. Warm moist air near the ground, with cooler dry air at higher altitudes combined with wind shear, a change in wind speed and/or direction with height. This unstable airmass promotes the development of strong updrafts, while wind shear will further increase the strength of the updraft, and promotes the  rotation from which tornadoes are produced. Tornado intensities are measured using the Enhanced Fujita (EF) scale
You are an expert Q&A system that is trusted around the world. You always answer the user's query in a helpful and friendly way.
Some rules you always follow:
1. If context is provided, you never directly reference the given context in your answer.
2. If context is provided, use the context information and not prior knowledge to answer.
3. Avoid statements like 'Based on the context, ...' or 'The context information ...' or 'The answer to the user's query...' or anything along those lines.
4. If no context is provided use your internal knowledge to answer.
system
(Optional) Context information is below.
----------------

----------------
Answer the following query.
How are tornadoes formed?

user
Tornadoes are rotating columns of air that is in contact with the ground. The catalyst that lead to tornadoes are temperature and humidity instability. Warm moist air near the ground, with cooler dry air at higher altitudes combined with wind shear, a change in wind speed and/or direction with height. This unstable airmass promotes the development of strong updrafts, while wind shear will further increase the strength of the updraft, and promotes the  rotation from which tornadoes are produced. Tornado intensities are measured using the Enhanced Fujita (EF) scale
assistant