It can happen quickly and far from a storm's center, inundating areas that don't typically flood.
Irma hit Florida on Sunday morning as a risky Category 4 storm, the second highest level on the five-step Saffir-Simpson scale.
Irma's powerful winds first blow offshore, essentially sucking the water away from the coast. Florida Gov. Rick Scott flew over the hard-hit but isolated Keys on Monday and said he saw "devastation" that included boats washed ashore and mobile homes pummeled by the storm.
The National Weather Service has told TMZ that the surge of water in Miami has gotten as high as 6 feet in some parts.
- Strong winds and flash flooding are still a threat as Irma spins into north Florida and toward Georgia over the next 24 hours. And from there, it goes up the coast toward the Tampa, St. Pete area, which is on a very large bay - the Tampa Bay - which is a attractive area, but it's very susceptible to storm surge, one of the most susceptible areas to storm surge in Florida. With this northerly track, we'll still likely see some impacts here in Mid-Missouri. Now those winds are reaching into Broward, toppling trees and power lines.
"If Tampa stays on the east side of the eye, we expect the storm surge to be worse than if the eye moves inland and the west side of the storm hits it", he said. Perhaps the days, weeks, and months after Hurricane Katrina set a low bar, but these past few weeks have shown us the worst of times being met with the best of America.
Meanwhile, in Florida, officials were telling people to prepare to hunker down for at least 12 hours once Irma makes landfall.