What prompts the queen to say the following quote:" Mad as the sea and wind, when both contend which is the mightier.: Explain the meaning.

Hamlet has just been with mother. Other than scaring the heck out of her and killing Polonius, Hamlet sees the ghost of Hamlet Sr. Unfortunately Gertrude (mother) can't see her dead husband. Hamlet talks to the ghost but to mother he looks like he is talking to the air hence she describes him as "Mad as the sea and wind." Both the sea and wind are mighty.