Hurricane IRMA Resulting Flood in Florida

After days of terrifying predictions, Irma arrived slammed into the Florida Keys on Sunday morning and the Florida mainland Sunday afternoon. It entered the state as a Category 4 hurricane and left as a still-powerful tropical storm. The related storm surge and inland flood so far is listed below:

• Hurricane Irma made landfall at Cudjoe Key at 9.10am, Sept 3rd, with sustained winds of 130mph. Massive storm surges, estimated at 10ft or higher, inundated buildings, overwhelmed roads and cut off the Keys from mainland Florida.
• Parts of downtown Miami flooded with rainwater and storm surges several feet deep, and tornadoes swept across swaths of south-eastern Florida. Winds toppled two construction cranes in downtown Miami, and all around south Florida brought down trees, live power lines, and street signs.

• The storm then swept along the south-western coast line before making landfall again at Marco Island and Naples, at 3.35pm, as a category three storm, with sustained winds of 120mph, blinding walls of rain, and gusts as strong as 140mph. As it approached Naples, the storm’s winds temporarily drained Tampa Bay, raising fears that the weakened hurricane would still wallop cities with surges.
• Hurricane Irma bared down on Fort Myers, north of Naples, within the hour as a category two storm, with sustained winds of 110mph. Storm surges have begun in and around Naples, with waters rising more than four feet in less than an hour and forecasts predicting as much as 10-15ft above ground level. From Naples earlier, went from negative surge to over 5 feet above ground level surge in 3 hours.

• Governor Rick Scott warned that south-west Florida could see storm surges of 10-15ft above ground – waves as tall as a one-story home, able to carry off people, cars, and mobile homes. Tampa should expect surges as large as five feet, and south-eastern Florida surges of three to six feet, high enough to float cars or envelop a person.

• The storm surge flooding would be the major concern for the coastal areas due to the strong wind. NOAA’s SLOSH model forecasts the inundation areas with maximum surge height from 10 to 15 feet for Tampa/Fort Myers.

• Rainfall occurring very quickly, at 2 to 4 inches per hour, will lead to flash flooding for urban areas.  Mountainous parts of the states will be especially vulnerable to flash flooding.

• Significant river flooding is likely over the next five days in the Florida peninsula and southeast Georgia, where average rainfall of 8 to 15 inches and isolated 20 inch amounts are expected. Based on 5 day rainfall forecast, there would be 10-15 inches of rainfall for the Central Florida, which might cause the riverine flood. FEMA has published the inland flood inundation areas based on this forecast.