TAMPA (AP)-- More than 170,000 homes and businesses in Florida have lost power and the center of Irma is about 90 miles southeast of Key West.
Florida Power and Light said on its website that more than half of those outages were in the Miami-Dade area, where about 600,000 people have been ordered to evacuate.
The company has said it expects millions of people to lose power, with some areas experiences prolonged outages.
The company said it has assembled the largest pre-storm workforce in U.S. history, with more than 16,000 people ready to respond.
As Irma's hurricane-force winds started to whip the Florida Keys, the storm stayed at a weakened 120 mph (190 kph) and took slow aim at Florida.
The National Hurricane Center says the storm's forward motion fell to 6 mph (10 kph) as the storm stuttered off the coast of Cuba. Forecasters say it could still increase in strength, but their forecast didn't show it.
The hurricane-force wind field stretched well over 100 miles. Forecasters say they are moving the forecast track slight west again.
The National Weather Service says the first hurricane-force wind gust has been recorded in the Florida Keys as Irma inches closer to the state.
The weather service says the Smith Shoal Light station recorded a 74 mph (119 kph) wind gust on Saturday night.
The center of Irma is headed toward the Keys and has sustained winds of 120 mph (193.11 kph).