Utility companies from Florida to Pennsylvania are working around the clock to restore power, but officials warn the task may take weeks to even months to complete in the hardest-hit areas.
Hurricane Ian made landfall on Wednesday as a Category 4 storm with winds estimated to be around 150 mph. During the height of the outages, more than 2.5 million customers were without power.
Many of those outages were customers of Florida Power & Light, Duke Energy, Tampa Electric and a few dozen other municipally owned electric companies and rural electric cooperatives.
More than 48 hours after the storm, the amount of customers without power has been cut in half due to the work of thousands of workers, but some of the biggest challenges lie ahead.
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More than 1 million customers are without power from Florida to Pennsylvania, but the Sunshine State is home to a large majority of the outages.
Of the state's 67 counties, outages are reported by PowerOutage.US in about a third of the state.
Outages stretch from northeastern parts of Florida through the central region and to the Gulf Coast.
The highest concentrations are around the Fort Myers, Port Charlotte and Sebring areas. These regions saw the most destructive winds and the heaviest rainfall.
Officials said it is only a matter of hours or even days before many of the outages are restored.
The state's largest electricity provider, Florida Power and Light, says they've been able to restore power to approximately 1.6 million customers.
And they say that 95% of customers should have electricity by this Sunday.
"It's a round-the-clock effort," said Florida Power & Light's Ed Devarona. "There's a lot of pride in what we do as utility workers. It's something that's shared not only by FPL, but all of those that come and assist us. Like I said, we have folks from 30 states, over 21,000 engaged in the effort.
Statewide, there are at least 42,000 utility and power crews working to get the lights back on to as many people as possible as fast as possible.
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The outages pale in comparison to Hurricane Irma, which knocked out power to 6.7 million electrical customers.
Hurricane Irma struck Florida on Sept. 10, 2017, and by Sept. 19, only around 100,000 customers were without power, according to the U.S. Energy Information Administration.
The administration reported the state had a recovery rate of about 9% of total customers per day until the hardest-hit areas were the only ones without power.
Restoration took several weeks to complete in the hard-hit areas and relied on water levels receding and roadway clearing before crews could address needed work.
Restoration rates after Hurricane Wilma of 2005 were significantly lower than in Irma despite only 36% of the state's customers being impacted.
The administration reports the recovery rate was only about 4% of customers per day.
Energy experts attribute the faster restoration efforts in more recent storms to utilities spending millions of dollars every year on hardening infrastructure and better preparation for natural disasters.
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