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Hurricane Irma weakened to a Category 1 storm early Monday after it whipped through southwest Florida and left nearly 4 million customers without power.
Irma was downgraded as it moved over the western Florida peninsula, the National Hurricane Center said. By 2 a.m. ET, it had sustained winds of 85 mph with its center 25 miles northeast of Tampa.
"Strong winds and flash flooding still a major risk with the storm as it moves into north Florida and toward Georgia over the next 24 hours," the center said.
Hurricane Irma hit southwest Florida on Sunday, downing power lines, uprooting trees and turning streets into rivers. It battered Florida's lower half, leaving a trail of tornadoes and storm-surge flooding as its core slowly made its way inland.
"The center of Irma will continue to move over the western Florida peninsula through Monday morning and then into the southeastern United States late Monday and Tuesday," the National Hurricane Center said.
The massive storm triggered evacuation orders for 5.6 million people, and made two landfalls Sunday.
The first one was over the Florida Keys, which Irma hit as a Category 4 hurricane with sustained winds near 130 miles per hour. The second one hit Marco Island, leaving the entire island without water and power, authorities said.
"We're all hanging in there, ready to get out there to help others as soon as it's safe to do so," Marco Island Police Chief Al Schettino said as the storm pounded his city Sunday.