The downfall and destruction of a hero in a tragedy is primarily the result of a tragic (flaw or action) in his or her character?

Flaw

Typically in tragedies, the end is not brought about by one specific action that a character takes or specific choice they make. Usually it is because that character has a fatal flaw that the tragedy happens. This flaw in their nature causes them to make poor decisions and act in certain ways, and is the root of the tragedy. 

D!!

spinning wind that forms a funnel and can cause a lot of damage