On Sunday, Tampa Bay and other bays and canals up and down the Gulf coast emptied out — a rare phenomenon that typically precedes a massive storm surge.

The worst is yet to come.

[protected-iframe id=”0e79f5dec3ff1c4a140906e4d75a1192-18340115-18946391″ info=”https://www.nbcnews.com/widget/video-embed/1043587651603″ width=”500″ height=”305″ frameborder=”0″ allowfullscreen=””]

Offshore winds coupled with a low tide have water levels six feet below normal. When this reverses, water levels are expected to be as much as 15 feet above normal.

Even though its downgraded to category 2, Irma is still very dangerous.

[protected-iframe id=”eb8e6a6972a7eef8eb4969fe0ccfb6c1-18340115-18946391″ info=”https://www.nbcnews.com/widget/video-embed/1043580483831″ width=”560″ height=”315″ frameborder=”0″ allowfullscreen=””]

Damage is widespread. More than 2.7 million people are without power.

Mike “Mish” Shedlock