Oil firms on Saturday cut nearly 91% of U.S. Gulf of Mexico crude oil production, roughly 1.65 million barrels, as Hurricane Ida makes its way toward major U.S. offshore oilfields, according to the Bureau of Safety and Environmental Enforcement.

The regulator also estimated that roughly 84.87% of natural gas production in the Gulf of Mexico has been shut in. 

Ida is forecast to reach a Category 4 hurricane before making landfall west of New Orleans. Louisiana residents on Saturday rushed to prepare for the storm, which could bring winds as high as 140 mph (225 kph) when it makes landfall.

Oil and gas companies evacuated 279 production platforms, representing 49.82% of the 560 manned platforms in the Gulf of Mexico, and shut in almost 91% of their typical offshore production as the storm approached, according to the offshore regulator.

The companies also moved 11 drill vessels off location and out of the storm’s path on Saturday.

The Gulf of Mexico federal offshore oil production accounts for 17% of the country’s crude oil production and 5% of its federal offshore dry gas production, according to the U.S. Energy Information Administration.

Andrew Lipow, president of Lipow Oil Associates in Houston, said Saturday that if the New Orleans refineries take a direct hit from a Category 4 storm, gas prices would likely rise by about 10 cents a gallon in the Southeastern and Mid-Atlantic markets.