Like Shakespeare's other tragic heroes, Lear suffers from a fault, a fatal flaw in his character. His is vanity and pride--hubris. Despite this weakness, however, it is Lear's strength that makes his downfall tragic. Shakespeare establishes Lear as an exceptional king and an exemplary ruler. The kingdom has flourished under his rule. Lear is introduced in the play at the height of his power, coming onto the stage with all the rich trappings of royalty. He sees himself as one of limitless power. In deciding to divide his kingdom among his daughters so that he can enjoy a pleasant old age, he believes he can give up his throne while retaining authority. Hubris.
The facts of Lear's downfall consume most of the play. His strength is tested. He sinks into madness. He recovers his senses. He is reconciled with Cordelia. He is changed by what he experiences. The hubris is replaced by humility--or not. Criticism disputes the exact dynamics of Lear's character.
However, the Lear who rages against the storm is a man who refuses to accept his own destruction in progress. When Lear reaches the end of his life holding the lifeless body of the one daughter who loved him, his destruction is realized. Lear's undoing would not have been so tragic if he had not had so far to fall and had not endured such profound suffering on his way to total despair.