(Bloomberg) -- As Harvey’s winds die down, trouble forTexas has just begun as days of flooding rains across the heart of U.S.energy production threaten the country’s fourth-largest city andleave farmers struggling to save horses, cows and crops.

Harvey smashed ashore as a Category 4 hurricane Friday nearRockport, Texas, a town left devastated.

It was the strongest storm to hit the U.S. since 2004 and brokea 12-year record span in which the nation avoided being hit by asystem ranked Category 3 or higher on the five-step Saffir Simpsonscale.

Since making landfall, Harvey has been downgraded to a tropicalstorm and come to a near-standstill over the town of Victoria.

Insured losses may be over $1B

The storm may spur $1.59 billion in damages, according tocatastrophe model results from Kinetic Analysis Corp., which said insuredlosses may be $1.11 billion.

“This will shift away from a wind concern and more into a floodconcern,” said Dan Pydynowski, a meteorologist with AccuWeatherInc. in State College, Pennsylvania. “The heavy rain and floodthreat will continue right into the middle of next week; we couldstill be talking about this thing by Tuesday, Wednesday andThursday of next week.”

The storm is striking a region that has a cluster of refineriesthat process 5 million barrels of oil a day. About 1 millionbarrels a day of crude and condensate refining capacity in Texashave been shut by companies including Valero Energy Corp.,according to company statements, government releases and peoplefamiliar with the situation. About 24% of Gulf of Mexico oilproduction had also been shuttered, along with the port of CorpusChristi, which ships the largest amount of U.S. crude overseas.

Crops, livestock & canceled flights

In addition to the energy threat, crops and livestock may struggleto cope with rising waters, while airlines have canceled flights atmultiple Texas airports. Because of where the storm has stalled,the Houston area could be in for days of torrential downpours andtornadoes.

Related: Water, water everywhere: Flood claim questionsanswered

Texas A&M University’s AgriLife Extension Service is helpingto set up animal sheltering sites around the state in case ranchersneed to relocate cattle or other animals, said Andy Vestal, aprofessor and extension specialist. Some livestock owners that areclosest to the coast have already been working to move animals tohigher ground, away from low-lying areas and tributaries, hesaid.

“We’ve never experienced 20 to 30 inches of rainfall in a48-hour period,” Vestal said by phone from College Station,Texas.

Roofs blown away

At least 100 modules storing cotton blew away in the Gregory area,said farmer Jeff McKamey, who owns a cotton gin that suffered minordamage when part of the piping and roof blew away. A storage tankcontaining sorghum at a local grain elevator in the town of Odem iscompletely gone and at least three other sorghum tanks collapsed atan elevator between Taft and Gregory, he said.

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“We’ve had the most cotton ever in storage in the history of SanPatricio County when the hurricane hit,” said McKamey, noting somecotton in the remaining storage modules may be too wet to process.“It’s just the worst possible time.”

At least 780 inbound and outbound flights were canceled atHouston’s two airports Saturday, with another 187 in Austin, SanAntonio and Dallas, according to Houston-based FlightAware, an airline tracking service. Close to 400flights in and out of Texas for Sunday were also scrubbed.

A driver moves through flood waters left behind by HurricaneHarvey, Saturday, Aug. 26, 2017, in Aransas Pass, Texas. (APPhoto/Eric Gay)

Power outages & heavy rain

At least 254,785 customers had lost power across the state,according to a Bloomberg survey of electric utility outage maps.The hardest-hit region, with about 200,000 knocked out, was fromBrownsville to Bay City, served by a unit of American ElectricPower Co.

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The outages will lead to a drop in electricity demand that couldcut into natural gas prices.

Pydynowski said Harvey’s position is allowing it to pullmoisture-laden air off the Gulf, called a feeder band, which willhelp keep it alive and promises more moisture for already-saturatedHouston.

“That feeder band is going to remain in the general vicinity ofHouston perhaps through Monday or even beyond,” Pydynowski said.“This is going to flood areas the don’t typically flood. It isgoing to have a tremendous impact on businesses, homes, property and the ability to travel inthe entire Houston area.”

As of 9 a.m. local time, Houston Southwest Airport had received6.4 inches of rain, according to the U.S. Weather Prediction Center in College Park,Maryland. From 15 to 30 inches of rain is forecast across theentire region, with some areas getting as much as 40 inches, thehurricane center said.

White Oak Bayou in Houston climbed nearly 16 feet since Fridayand was forecast to rise another 25 feet by Sunday, according tothe National WeatherService. The Buffalo Bayou at Piney Point Village, just west ofcentral Houston, is forecast to set a record, while the waterway isexpected to rise by more than 30 feet near Shepherd Drive in thecity itself.

Sustained winds of 70 miles per hour

Harvey had maximum sustained winds of 70 miles (113 kilometers) perhour, the hurricane center said in an advisory at 1 p.m. localtime.

The current track forecast shows the storm meandering aroundsoutheastern Texas gradually weakening to a tropical depressionearly next week. While the track means heavy rains will fallunabated, there is a glimmer of good news in the forecast if itholds — Harvey won’t drift into the Gulf and restrengthen.

Related: 3 strategies for recovering from floodlosses

“It still might re-intensify to a Category 1 again later thisweek, but the nightmare scenario of another Category 3 landfalllooks highly unlikely now,” said Todd Crawford, chief meteorologistat The Weather Company in Andover, Massachusetts. “The big storygoing forward will be the epic amounts of rainfall in a largearea.”

Forecasters watching system over Florida

In addition to Harvey, hurricane center forecasters are watching alow pressure system over Florida that could develop into a tropicalor sub-tropical storm early next week. The system will likely beshort lived, but could bring heavy rain to Florida.

In addition to its economic impact, Harvey prompted thousands ofresidents along the Texas coast to flee their homes and causedGovernor Greg Abbott to declare an emergency. It was the firstCategory 4 storm to hit Texas since 1961 and the first to hit theU.S. since 2004. Katrina, the most costly hurricane in U.S. history,came ashore as a Category 3 storm in 2005.

Trump approved major disaster declaration

If the storm does significant damage to the refineries in theregion, or causes the Colonial pipeline to go offline, the effectscould ripple to other parts of the country that rely heavily on theGulf Coast for fuel supplies. Gasoline futures settled at athree-week high Friday as the storm approached.

President Donald Trump approved a major disaster declaration,making federal assistance available to supplement state and localrecovery efforts. The U.S. EnvironmentalProtection Agency waived certain fuel requirements for gasolineand diesel in eastern parts of the state to allay concerns of fuelshortages.

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