Houston’s work week will begin underwater as Tropical Storm Harvey unleashes heavy rains on the heart of U.S. energy production. There’s no telling how long it will be until things get back to normal. The storm has led to record flooding across a city that’s dealt with deluges before. Elected officials, meteorologists and emergency managers all say there has never been anything like this there, and the downpour could last for days. “Houston has another 100 hours of this,” said Todd Crawford, chief meteorologist at The Weather Company in Andover, Massachusetts. “Words really can’t express the impacts this will have, when all is said and done. There is no historical comparison. It is simply a tragedy of epic proportions.” Harvey smashed ashore near Rockport, Texas, Friday as a Category 4 hurricane. As the winds subsided Sunday to about 40 miles (64 kilometers) per hour, from 130 miles per hour earlier, rain and flooding took over as the main threat from a storm that’s the strongest to hit the U.S. since 2004. As much as 25 inches of rain has already fallen and another two feet is possible, the National Hurricane Center said at 5 p.m. New York time. Two deaths are attributed to the storm, which has also halted about one quarter of oil and natural gas production in the Gulf of Mexico and more than 10 percent of U.S. refining capacity. In addition to energy, crops, livestock and drinking water are under threat. Airlines had canceled almost 3,000 flights at multiple Texas airports Sunday and another 1,389 were scrubbed for Monday, according to FlightAware, a Houston-based airline tracking service. “It is very bad flooding, rivaling the Katrina disaster in some cases,” Brett Rossio, a meteorologist with AccuWeather Inc. in State College, Pennsylvania, said by telephone. “Some places will get greater than 30 inches; this is very deep, tropical moisture that is lifting northward.” BNSF Railway Co. said Sunday that heavy rain and unprecedented flooding is causing “significant service disruptions” in the Houston area and throughout southeastern Texas. Intermittent amounts of water will be released from the Addicks and Barker reservoirs because of the severe flooding in Houston, the U.S. Army Corps of Engineers Galveston District said in a statement. The dams are designed to protect Houston and the Houston Ship Channel from deluges. Drifting Storm Harvey, which had been sitting northwest of Victoria, Texas, has begun to slowly drift toward the Gulf of Mexico, the hurricane center said. The worst that could happen is it re-intensifies Monday into Tuesday, before once again swinging back into the southeastern Texas coast, Rossio said. A tropical storm warning is in place from Port O’Connor to Sargent and a watch was issued Sunday for the coastline north of there to San Luis Pass in anticipation of Harvey’s return to the Gulf. San Luis Pass is at the southern tip of Galveston Island. At least 19 points across southeastern Texas were expected to set flooding records, said Greg Waller, a service coordination hydrologist with the National Weather Service in Fort Worth, Texas. Buffalo Bayou, that runs through Houston, broke its old record for flooding at 5:45 a.m. Sunday and was forecast to stay above that mark until Wednesday. “The thing that is even worse when you have this much water is you get contamination of the clean water,” Rossio said. “A lot of places are going to lose their drinking water.” Major roadways in Houston were flooded by Sunday morning, some with several feet of water. Motorists have been stranded on freeways for hours because off-ramps are inundated. The city’s CBS television affiliate was knocked off the air by floodwaters Sunday, according to tweets by station personnel, and Houston Mayor Sylvester Turner opened the city’s downtown convention center to residents left homeless by the storm. “The word we’re using is catastrophic,” Waller said. ‘We are trying to discourage people from comparing this to past events. Don’t rely on past events. If you think you know what the river will do, you don’t because the river has never done this.” Disaster Declaration President Donald Trump approved a major disaster declaration, making federal assistance available to supplement state and local recovery efforts. The U.S. Environmental Protection Agency waived certain fuel requirements for gasoline and diesel supplies in Texas, including the Dallas-Fort Worth area, to allay concerns of fuel shortages. The Federal Emergency Management Agency, meanwhile, is prepared to be in the Houston area “for years” as the fourth-largest U.S. city takes the brunt of rainfall and flooding from Harvey, Administrator Brock Long said on CNN’s “State of the Union” program on Sunday. Damage from the initial strike won’t tell the whole story, said Chuck Watson, director of research and development, at Enki Holdings LLC in Savannah, Georgia. “If it was a traditional hurricane it would be a $2 billion storm, maybe $3 billion, but that is not what this storm is about,” Watson said. Agriculture Havoc The rain is wreaking havoc on the largest U.S. cotton producer, hitting Texas at a time when many farmers are storing excess supplies on fields following a bumper harvest. At least 100 cotton storage modules—capable of holding 13 to 15 bales—blew away near the coastal community of Gregory, Texas, said Jeff McKamey, a farmer who owns a cotton gin that suffered minor damage when part of the piping and roof blew away. “We’ve had the most cotton ever in storage in the history of San Patricio County when the hurricane hit,” McKamey said. “It’s just the worst possible time.” Ports at the Texas Gulf account for about 24 percent of U.S. wheat exports, 3 percent of corn shipments and 2 percent of soybeans, according to the Soy Transportation Coalition, citing data from the U.S. Department of Agriculture. The threat to shipments of corn and soybeans, the top U.S. crops, comes from Harvey’s potential impact in Louisiana and the Gulf of Mexico. About 60 percent of American soybean exports depart from the region, as do 59 percent of corn shipments, Mike Steenhoek, executive director for the group, said Thursday in an email. Delayed Loading “Heavy rain will delay the ability to load ocean vessels and unload barges,” Steenhoek said in an email. “Heavy winds and storm surges, if they occur, could damage the export terminals.” Harvey was downgraded to a tropical storm after making landfall overnight on Friday night. The death toll, though, is expected to rise as emergency crews were yet to reach some of the hardest-hit areas, the Associated Press reported. On Sunday, Houston police were advising residents to stay in their houses, even if there was some flooding there. “Non-life threatening water inside home is safer than going outside,” the Harris County Sheriff’s Office tweeted on Sunday morning. “Difficult & scary, but we’ll get to you. Pls shelter in place. Be Safe.” Shuttered Production Electricity service had been cut to about 291,300 customers in southeast Texas as of 3:30 p.m. local time, according to a tally of utility blackout reports by Bloomberg. The severe flooding was hampering the ability of crews to assess damage and restore service in certain areas, the Washington-based Edison Electric Institute said.   For more information on tropical storms such as hurricanes and typhoons, click here Harvey’s position is allowing it to pull moisture-laden air off the Gulf, called a feeder band, which will help keep it alive and promises more moisture for Houston, said Dan Pydynowski, a meteorologist with AccuWeather Inc. in State College, Pennsylvania. “That feeder band is going to remain in the general vicinity of Houston perhaps through Monday or even beyond,” Pydynowski said. “This is going to flood areas the don’t typically flood. It is going to have a tremendous impact on businesses, homes, property and the ability to travel in the entire Houston area.” Along with the rain, the coast land could face tornadoes, the hurricane center reported in an advisory. If the storm does significant damage to the refineries in the region, the effects could ripple to other parts of the country that rely heavily on the Gulf Coast for fuel supplies. Gasoline futures settled at a three-week high Friday as the storm approached. “If you live through this event it is one you will remember for the rest of your life,” Waller said.