(Bloomberg) -- Hurricane Irma bulked up ahead of an all butcertain collision with southern Florida after devastating achain of Caribbean islands and threatening to become the mostexpensive storm in U.S. history.

While the life-threatening hurricane weakened slightly, Irmagrew in size meaning that most of the state will facehurricane-force winds as it cuts a path through the peninsula intoGeorgia.

Now a Category 4 storm with top winds of 150 miles (241kilometers) an hour, Irma will maintain its strength until itstrikes Florida early Sunday, the U.S. National Hurricane Center said in anadvisory around 11 a.m. Eastern time. The storm has alreadyleft at least 11 people dead and thousands homeless across theCaribbean.

'Long and horrible day on Sunday'

“Much of Florida, especially the southern half, is in for a reallylong and horrible day on Sunday,” said Todd Crawford, leadmeteorologist at The Weather Company in Andover, Massachusetts.Another example of “the power of nature on a heavily populatedpart of the U.S. coastline is imminent, and the costs will begreat.”

Mandatory evacuations were issued for the Florida Keys and otherareas. Around 650,000 people were told to leave Miami-Dade,the largest evacuation ever attempted in the county. PresidentDonald Trump’s Mar-a-Lago estate was ordered to be evacuated alongwith the rest of Palm Beach following forecasts of catastrophicwinds and a powerful storm surge.

Irma is one of three hurricanes churning in the Atlantic Basin.Jose, the third major hurricane of the 2017 season with topwinds of 150 miles per hour, is forecast to turn northeast and missthe U.S. In the Gulf of Mexico, Katia strengthened as it movedslowly toward Veracruz, Mexico, where it’s forecast to come ashoreearly Saturday. The country was also struck by a powerfulearthquake on Friday, shaking buildings in the capital andtriggering a tsunami warning.

Hurricane-force winds extend for 140 miles

Irma’s hurricane-force winds now extend for 140 miles, creating adanger zone that would extend from West Palm Beach on theAtlantic coast to Fort Myers on the Gulf of Mexico. That’s creatingan “insurance industry nightmare” as every county in the statecould experience damaged roofs and power outages so vast itoverwhelms utility repair efforts, said Chuck Watson, a Savannah,Georgia-based disaster modeler with Enki Research.

Damages could easily top $135 billion in Florida, with othereconomic losses pushing the price tag as high as $200 billion,Watson said. Preliminary estimates show losses across the Caribbeannearing $5 billion, Josh Darr, lead meteorologist with insurancebroker JLT Re Ltd. wrote in his blog Friday.

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

'Throw a wrench into the insurance industry'

“Wind damage is totally going to throw a wrench into the insuranceindustry,” Watson said. “You are talking about companiesfailing.”

Insurers including XL Group Ltd. and Everest Re Group Ltd.recovered some ground after falling 5.1% and 6.8T respectivelyThursday. The storm may knock out power to more than 3 millionhomes and businesses, curb natural gas demand in one of the largestU.S. markets and threaten $1.2 billion worth of crops in Florida— the nation’s top grower of fresh tomatoes, oranges, greenbeans, cucumbers, squash and sugarcane.

Irma was 405 miles southeast of Miami and is forecast toapproach the north coast of Cuba and the central Bahamas beforestriking southern Florida Sunday morning, the hurricane centersaid.

Irma comes just two weeks after Hurricane Harvey smashed ashorein Texas, knocking offline almost a quarter of U.S. oilrefining capacity and causing widespread power outages andflooding.

In other storm news

• Orange juice futures rallied to the highest level sinceMay.
• Airlines have canceled thousands of flights.
• Miami’s financial district was rapidly emptying out beforelandfall.
• The storm threatens to turn years of strong returns for hedgefunds and other catastrophe-bond buyers into losses almostovernight and may affect how much money bondholders receive ontheir Puerto Rico Electric Power Authority bonds.
• Irma’s chemical fallout could be worse than Harvey’s as Floridaplants are filled with potentially explosive material.

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