Crude oil soared to a record of more than $70 a barrel in New York after Hurricane Katrina forced companies including Exxon Mobil and Chevron to shut operations in the Gulf of Mexico.

Oil had its biggest gain in 29 months while gasoline and heating oil reached records as Katrina, one of the most powerful storms to hit America, crossed the Gulf, source of 30% of the country’s oil output and 24% of its natural gas.

“Forecasters are saying Katrina could do more energy damage than any storm in recent years,” an economist with Wachovia in Charlotte, N.C., Jason Schenker, said before the start of trading. “It’s not just that there’s going to be outages for the next couple of days. With shutdowns and damage at platforms and refineries, the bullish impact could be felt for the rest of the year.”

Crude oil for October delivery rose as much as $4.67, or 7%, to $70.80 a barrel in electronic after-hours trading on the New York Mercantile Exchange. It was at $69.86 a barrel at 7:55 a.m. Singapore time.

Natural gas for September delivery gained as much as 23% to $12.07 per million British thermal units, the biggest one-day rise for 11 months. It was at $11.569 at 8:04 a.m. Singapore time.

Japanese stocks dropped, led by exporters such as Sony, after an industry report showed a bigger-than-expected drop in American consumer confidence and oil prices surged.

Royal Dutch Shell said it has shut 420,000 barrels of daily oil production in the Gulf because of Katrina. The Louisiana Offshore Oil Port, which handles about 11% of American imports, closed August 27 and has since halted all oil movements to shore.

Exxon Mobil, the world’s largest oil company, evacuated workers and shut about 50,000 barrels of daily oil production and 300 million cubic feet of gas, a spokeswoman, Susan Reeves, said. The company removed 430 employees and contractors from its Gulf facilities last night, she said.

Chevron, the second-largest American oil company, did not have figures immediately about the amount of oil and natural gas that will be shut, a spokesman, Matt Carmichael, said. “We are still doing the math,” he said.

Katrina is a Category-5 storm, the most severe on the Saffir-Simpson scale of hurricane strength. It would be only the third storm of that magnitude to hit America since the government began keeping storm records.

States of emergency have been declared in Louisiana and Mississippi. New Orleans, a city of 500,000 within a metropolitan area of 1.3 million, is being evacuated of all but essential personnel. Much of the city, 100 miles upriver from the Gulf, lies below sea level.

Hurricane Katrina may cost insurers more than $30 billion, which would make it the most expensive storm to ever hit America, a storm modeler said.

“The storm is more severe than we’ve thought; it’s turned into a monster,” a senior oil analyst with Deutsche Bank Securities, Paul Sankey, said. “The amount of lost production is equal to almost all the spare capacity in the world.”