By the time Hurricane Michael slammed into the Florida Panhandle on Wednesday afternoon, it had swollen into one of the most powerful storms ever to strike the U.S. mainland, threatening homes with a combined value as high as $19 billion.

The new estimate from property analytics firm CoreLogic is 42 percent higher than an early projection, reflecting how much the tropical cyclone strengthened over the course of a single day from abnormally warm waters in the Gulf of Mexico. With winds as strong as as 155 mph, Michael is the strongest storm to strike Florida since Hurricane Andrew in 1992 and the worst to hit the Panhandle since at least 1900.

The Category 4 hurricane came ashore near Mexico Beach, a tourist town about midway along the lightly populated 200-mile Panhandle, as the northwest coast of Florida is known. While the damage will be significant, it would have been worse had the storm struck land further west, David Smith, a science and analytics leader at CoreLogic, said in a presentation on Wednesday.

Michael will probably retain tropical storm-force winds as it angles east across Georgia, South and North Carolina, and Virginia in the next several days, said Daniel Betten, a meteorologist with the firm. It's likely to cause flash-flooding in spots, particularly those already drenched by Hurricane Florence, but not over wide swaths of land like its predecessor.

Michael is a "relatively fast-moving storm," said Tom Jeffrey, principal hazard scientist with CoreLogic. "Whereas Florence churned off shore and drove a large volume of water onto shore, this storm is going to move more quickly." The initial peak of the storm surge will be higher, at 14 feet, but it won't push seawater onto land for as long a period of time, he explained.

Rescue workers have gathered trucks loaded with tons of food, water, and other critical supplies, including 1.5 million ready-to-eat meals and 1 million gallons of water to help the affected areas of the state, said Florida Gov. Rick Scott.

"There’s nothing our state cannot recover from, because there is no state that cares, loves, or comes together like Florida," he said on social media platform Twitter.

With Election Day less than a month away, the crisis was seen as a test of leadership for Scott, a Republican running for the Senate, and Tallahassee Mayor Andrew Gillum, the Democratic nominee for governor. Just as Northern politicians are judged on how they handle snowstorms, their Southern counterparts are watched closely for how they deal with hurricanes.

"We can replace material things, we can’t replace life," Gillum told Tallahassee residents in a video message urging them to take advantage of government emergency shelters that could withstand the storm.

"It’s not the comforts of your own home, but it's absolutely sturdy and safe, and you can be assured that you will make it through this storm safe and come out on the other side," he said.

President Trump, who declared a pre-landfall emergency in Florida on Tuesday that freed up federal funds to deal with the disaster, said the federal government is prepared to help.

"This is a top priority," he told reporters at the White House on Wednesday. Scott, who suspended his Senate campaign against incumbent Democrat Bill Nelson to deal with the storm, had warned the White House that state and local government capabilities were already strained by recovery efforts after Hurricane Irma in 2017 and hurricanes Irma and Hermine the year before.

Private insurance payouts from Michael may reach $4 billion for wind damage and $500 million for the storm surge, CoreLogic estimated. Most of the residential damage will be covered by the National Flood Insurance Program, a government initiative that serves areas where businesses have deemed the risk too high.

Progressive Insurance might make after-tax claims payments of $67 million, compared with $40 million for Travelers and $39 million for AIG, Randy Binner and Ryan Aceto, analysts with B. Riley Financial FBR, projected in a report on Tuesday.

"The losses broadly fall within our loss expectations" for the end of the year, they noted. Hurricane season in the Atlantic stretches from June through Nov. 30, and October is typically among the most active periods.

— With assistance from the Associated Press.