Meanwhile, the US Hurricane Centre is saying the spate of strong storms such as Rita, Katrina and Ivan are due to the Atlantic being in the midst of a naturally occurring cycle of increased activity.
Rita is threatening up to 18 Texas oil refineries with a combined capacity of four million barrels per day, or 23% of the nation’s total refining capacity, said the US Energy Information Administration.
The hurricane centre yesterday called the storm "extremely dangerous," with maximum sustained winds of 265 m per hour, and said it was likely to draw even greater power from the warm Gulf waters.
Rita, now a Category 5 storm, could surpass Katrina which three weeks ago became the most expensive natural disaster in US history. But Rita could also weaken slightly as Katrina did, from Category 5 to 4, just before it came ashore.
Rita might hit the US mainland anywhere from the southern Texas coast up to western Louisiana, said the hurricane centre.
The centre’s director told a congressional panel that he believed the Atlantic Ocean had entered a cycle of increased hurricane activity, which paralleled the last increase that started in the 1940s and ended in the 60s.
Max Mayfield told the panel that this lull ended in 1995 and then “it was like somebody threw a switch,” and the number of hurricanes in US waters rose dramatically.
The increased activity was a natural cycle in the Atlantic Ocean that fluctuated every 25 to 40 years and several more tropical storms were likely this year, he said.
Since record keeping started in 1851, the record number of tropical storms reported in one year was 21 in 1933.
Rita is the 17th major storm of this year's Atlantic hurricane season, which runs from June to November.
About 47% of normal Gulf gas output and 73% of oil production was now shut as the area braces for Rita’s arrival, said the Minerals Management Service.
Oil companies, including Royal Dutch Shell, BP, Exxon Mobil and Chevron, have already evacuated hundreds of workers from rigs and platforms near the two states. Refiners have cut production at several plants and some have also started evacuating non-essential personnel.
About 44% of the US refining capacity is in Louisiana and Texas. About 30% of US oil production comes from Gulf of Mexico platforms.
The largest US refiner, Valero Energy Corporation, has already cut production at plants in Houston and Texas City and evacuated non-essential workers, in preparation for Rita’s landing which could occur in the next three days or sooner if the storm gathers strength.
The EIA said Rita's current projected path put it south of some of the major oil-producing areas in the Gulf of Mexico.
But it said if the storm hit the western Gulf of Mexico, the impact could be significant as areas of petroleum infrastructure untouched by Katrina would be damaged.
Meanwhile, oil prices have rocketed back up to over US$67 per barrel, reaching US$67.15 on the New York Mercantile Exchange, while futures touched US$68.27, the highest since September 2, during yesterday’s trading.
