(Bloomberg) – Hurricane Irma hopscotched up Florida's west coast Sunday, making two landfalls and driving a wall of water and winds that submerged Miami and had the Tampa Bay area readying for a deluge of a sort unseen in decades.

220-mile reach

Irma's 220-mile reach is so long that cities on the state's southern and eastern extremes were hit with surges and winds high enough to topple cranes in Miami, where the flooded Brickell financial district looked like a swift river. Early reports suggested that the low-lying Florida Keys were devastated, with photos showing cars submerged almost to their roofs. The U.S. military began a relief mission, sending tarpaulins, food, water and medical supplies.

Just over two weeks after Hurricane Harvey struck the heart of U.S. energy production in Texas, Irma is threatening another region. By 5 p.m. Sunday, it was a Category 2 storm with top winds of 110 miles per hour, the U.S. National Hurricane Center said. While initial estimates saw a $200 billion loss, as the storm weakens on its northerly trek that number could fall.

Its path forced the largest evacuation in Miami-Dade County history and sent millions of Floridians fleeing the state's first major hurricane since Wilma in 2005. It has already laid waste to the small island of Barbuda, killed at least 25 people and left thousands homeless across the Caribbean.

1st landfall over lower Keys as Cat 4

In the U.S., the storm made landfall over the lower Keys about 9 a.m. with Category 4 winds hitting 130 miles per hour (209 kilometers) before starting to weaken. It made a second landfall at Marco Island in the afternoon, then passed 5 miles north of Naples as it headed up the state's west coast toward Alabama and Georgia.

By Sunday afternoon, Irma had knocked out power to almost 2.4 million customers, paralyzed tanker traffic and shut about 6,000 gasoline stations. As the storm makes its way up Florida's west coast, it'll also threaten more than $1 billion worth of crops.

A sprinkler spews out water after a tree came down on a fence in Surfside, Fla., during Hurricane Irma on Sunday, Sept. 10, 2017. (AP Photo/Wilfredo Lee)

No power for weeks for some customers

NextEra Energy Inc.'s Florida Power & Light utility warned Sunday that some customers may go without power for weeks and parts of its system may need to be rebuilt “from the ground up.” The company took offline one of two reactors at its Turkey Point nuclear plant south of Miami. Ports critical to supplying the state with gasoline and diesel were also closed, and energy companies including Exxon Mobil Corp. shut fuel terminals.

Irma's last-minute shift westward may exacerbate damages for victims who expected to miss the worst of the storm, and then were left with too little time to prepare.

“Most people expected it to impact the east coast rather than the west coast,” said Duncan Ellis, the U.S. property practice leader at Marsh & McLennan Cos.' main brokerage unit. “It took a turn to the left, and that's caused a bit of a scramble in getting properties ready for the storm and evacuations.”

The storm is collapsing before reaching the Tampa-St. Petersburg area, and that could drive damages to under $49 billion, with insured losses at about $19 billion, said Chuck Watson, Enki Research disaster modeler, in Savannah, Georgia. It could save insurance companies.

“There may yet be a Florida insurance market on Tuesday,” Watson said.

Total losses from Hurricane Katrina reached $160 billion in 2017 dollars after it slammed into New Orleans in 2005.

An American flag is torn as Hurricane Irma passes through Naples, Fla., Sunday, Sept. 10, 2017. (AP Photo/David Goldman)

Storm's impact rippled across the nation

The storm's impact rippled across the nation and beyond. In Atlanta, shoppers besieged grocery stores, stripping shelves of water, bread and milk. South Carolina opened shelters to accommodate an expected flood of refugees; in Florida, 6.5 million residents had evacuated.

Military ships and aircraft delivered thousands of tarps, 40 pallets of food, medical supplies and water to the Virgin Islands, while evacuating more than 70 patients, according to a news release from the U.S. Northern Command. Ships were in position to begin search and rescue work when weather permits.

The Defense Logistics Agency sent about 5,000 gallons of water to Haiti; 100,000 gallons of gasoline and diesel to Warner Robins Air Force Base in Georgia to support the Federal Emergency Management Agency; and millions of meals to staging areas on bases in Alabama and North Carolina.

In Washington, the House of Representatives said lawmakers shouldn't expect planned votes Monday because of absences caused by the storm, according to an announcement by the office of Majority Leader Kevin McCarthy. And President Donald Trump described the hurricane as “a storm of enormous destructive power.”

A crane atop a high-rise under construction in downtown Miami collapsed Sunday, Sept. 10, 2017, amid strong winds from Hurricane Irma. The crane collapsed in a bayfront area filled with hotels and high-rise condo and office buildings, near AmericanAirlines Arena, according to a tweet from the City of Miami. (Gideon J. Ape via AP)

Ferocious winds in Miami

Miami was the first major city to feel it. At least two construction cranes collapsed under the force of ferocious winds, leaving them teetering on the sides of buildings under construction.

Firefighters ventured out in an armored vehicle to inspect one on downtown Biscayne Boulevard, said spokesman Captain Ignatius Carroll. Fire officials asked neighbors to take refuge on the other side of their buildings.

“We don't want anyone looking out their windows or going near there, because they could be hit by debris,” Carroll said.

Along flooded Brickell Avenue, the city's financial district, side streets became tributaries and wind whipped up whitecaps on water coursing by office buildings.

At the J.W. Marriott hotel in the neighborhood, guests were pulled into an emergency shelter in the fifth-floor ballroom. Hotel staff set up a video screen to play movies, provided board games and even a special room for pet care. Speakers played soothing music, and a giant video screen cycled images of tropical beaches.

Outside, winds ripped the roof off a building north of the financial district. Video showed a huge swath of roof peeling away and smashing onto other structures nearby in a cloud of debris. No injuries were reported, Carroll said.

Worse could be in store farther north. The storm's track along Florida's west coast “is almost, if not, a worst-case scenario for Tampa Bay,” said Rob Miller, a meteorologist at AccuWeather Inc. in State College, Pennsylvania. “It shoves all the water into Tampa Bay and then shoves it right into downtown.”

Water floods a street in the business district as Hurricane Irma passes through Naples, Fla., Sunday, Sept. 10, 2017. (AP Photo/David Goldman)

Shallow continental shelf along Florida's west coast

The continental shelf there is relatively shallow for as much as 90 miles offshore, said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan.

On the city's Bayshore Boulevard, the waters of Tampa Bay had receded as much 200 feet Sunday morning. Detritus such as discarded beer cans and sea shells could be seen atop muddy sand that until recently had been submerged.

Downtown, the commercial center, the port and cruise terminal were virtually deserted as rain increased and winds picked up. Buildings were fortified with boards over windows and three-foot walls of sandbags at the doors.

Geoff Rutland, 40, a lifelong Tampa resident, and his wife, D.J., decided to ride out the storm with five other families and a pastor in the Crossing Jordan Family Worship Center.

At an ice vending machine about a block away, there was a line as much as 30 deep. He helped others tie ice bags, fill coolers and keep calm. During a phone interview he repeatedly paused to refuse tips from those he helped.

“I'm not here for money,” he said. “I'm just here to help people.”

Continue for more Hurricane Irma photos:

Heavy rains flood the streets in the Coconut Grove area in Miami on Sunday, Sept. 10, 2017, during Hurricane Irma. (AP Photo/Alan Diaz)

A man looks over the pounding surf caused by Hurricane Irma in the Wild Dunes Resort community of the Isle of Palms, S.C., Sunday, Sept. 10, 2017. (AP Photo/Mic Smith)

Fallen trees are seen during Hurricane Irma, in Fort Myers, Fla., Sunday, Sept. 10, 2017. Hurricane Irma set all sorts of records for brute strength before crashing into Florida, flattening islands in the Caribbean and swamping the Florida Keys. (AP Photo/Gerald Herbert)