US Stock Market: Hurricane Irma is already causing Florida insurance stocks to plunge

Shares of Homeowners Choice, Universal Insurance Holdings and Heritage Insurance Holdings were down by double digits.

Reinsurers XL Group and Everest contributed some of the largest losses to the S&P 500's decline, down 4.3 and 3.7 percent respectively.

While Irma is still a few days off the United States coast, insurers are bracing for storm surges, flooding and deadly winds.

Read more: Hurricane Irma is already causing Florida insurance stocks to plunge

Hurricane Harvey Energy Crisis Could Be Nightmare For U.S. Economy- by Ellen R. Wald

On Tuesday, August 29, over 26 inches of rain fell in Port Arthur, Texas. The 50,000 residents of that city, north and east of Houston, are suffering severe flooding and personal loss. Port Arthur is also the home of the largest refinery in the United States, Motiva, which has been shut down due to massive flooding. In addition, the nearby Valero Energy VLO -0.45% and ExxonMobil XOM +0.30% refineries were shut and the Colonial Pipeline (distributing refined products across the Southeast and north to Tennessee) has been disrupted. About 22% of U.S. refining capacity is offline due to the natural disaster. All told, it now appears that the impact Harvey will have on the energy industry is worse than expected and could very well, in a worst case scenario, lead to a serious macro-economic problem.

Read mor: Hurricane Harvey Energy Crisis Could Be Nightmare For U.S. Economy