What is a good thesis statement for tornadoes?

A good thesis statement is generally a sentence at the beginning of a reasearch paper. This statement establishes the direction a paper will take in analyzing and and interpreting an issue or concept.

Some thesis statements might include:

• "The frequency and severity of tornadoes in the United States has not increased in recent decades."
• "Exceptionally deadly tornado outbreaks have played pivotal roles in the development of a tornado warning system."