Hurricanes begin over warm ocean waters as clusters of thunderstorms that develop rotating winds due to the Coriolis effect. As the storm strengthens, winds of up to 125 mph circulate around the eye wall with heavy rain and strong winds extending outward. When hurricanes make landfall, they can cause devastating damage through strong winds, heavy rainfall, and storm surges that produce severe coastal flooding. Some of the worst hurricane disasters have destroyed thousands of homes and killed hundreds of people. Global warming may be increasing hurricane activity by creating more regions with warm ocean temperatures suitable for hurricane formation.