Hurricane Irma made landfall on Sunday morning along the Florida Keys, with sustained winds of 130 mph.
Although Irma has weakened some, this is still a rare and powerful storm that will have devastating effects on parts of the Florida peninsula, and will disrupt the entire state for days.
Irma's forecast track is pretty well locked in, as the storm should essentially cruise up the western coast of the state—with the center remaining just on or off shore—before moving into the Florida panhandle, Georgia, and Alabama before dying over the southeastern United States.
Winds, storm surge, and inland rain are all major threats for Florida.
But for scientists, the key determinant of hurricane intensity is central pressure—the extent to which a storm’s center is lower than the Earth’s normal sea-level pressure of 1013.25 millibars.
By developing a low central pressure, a storm is better able to pull in warm air and moisture to its center, and this rising air creates swirling thunderstorms.