FORT MYERS, Florida, Dhu-AlHijjah 19, 1438, September 10, 2017, SPA -- Hurricane Irma gained strength as it was set to make landfall in Florida on Sunday with a double barrel threat of destructive winds and life-threatening storm surges, prompting one of the largest evacuations in U.S. history, Reuters reported. The storm, which went on a deadly march up Cuba's northern coast a day earlier, was a Category 4 hurricane about 40 miles (65 kms) south-southeast of Key West, Florida, as of 5 a.m. EDT (0900 GMT) on Sunday with maximum sustained winds of 130 mph (210 kph), the National Hurricane Center said. It was on a path that would take it along the state's Gulf of Mexico coast near population centers including Tampa and St. Petersburg, it said. Storm surges pushed by a high tide were forecast to be as high as 15 feet (4.6 metres) for low-lying area along the state's southwest coast on Sunday, which could produce catastrophic flooding for thousands of homes. "This is a life-threatening situation," the NHC said. Irma, which killed at least 22 people in the Caribbean, was likely to cause billions of dollars in damage to the third-most-populous U.S. state. Wind gusts near hurricane force began to batter the Florida Keys late on Saturday, the NHC said, with Key West seeing gusts of more than 80 mph on Sunday morning and water levels about 2 feet (61 cms) above normal. The area was expected to feel the full brunt of Irma starting at around 7 a..m. to 8 a.m. Thousands of people spent the night in emergency shelters ahead of the storm expected to rip through Florida's southwestern archipelago on Sunday morning as a Category 4 storm, the second-highest designation on the Saffir-Simpson scale. Irma should weaken as it moves inland over the Florida panhandle and southwestern Georgia on Monday afternoon, the NHC said. The NHC has put out a hurricane warning and a tropical storm warning stretching through almost all of Florida into Georgia and South Carolina - an area where more than 20 million people live. The city of Miami imposed a curfew until 7 a.m. on Sunday and more than 275,000 customers in Florida were without power, utilities reported. Irma comes just days after Hurricane Harvey dumped record-setting rain in Texas, causing one of the costliest natural disasters in U.S. history. --SPA 14:09 LOCAL TIME 11:09 GMT www.spa.gov.sa/w484278