US Gulf of Mexico operators raced on Monday to shut down production and finish preparing for Hurricane Sally as it lumbered towards the US Gulf Coast, shutting in more than 497,000 barrels of oil per day, or 26.8% of the region’s oil production, according to data from the nation’s Bureau of Safety and Environmental Enforcement (BSEE).

The agency’s estimate, based on reports from 30 companies, also finds that more than 759 million cubic feet per day of natural gas, or 28% of current production, has been shut in as the slow-moving Hurricane Sally prepares to make its final push into the area, the second significant hurricane to impact oil and gas activity in the last month.

The production shut-ins come just as platforms and facilities were starting to come online post-Hurricanes Marco and Laura that swept through the Gulf of Mexico two weeks ago, forcing the temporary suspension of 1.5 million barrels of oil per day of output.

According to Rystad Energy, Hurricane Sally could potentially shut down as much as 1 million barrels of oil per day, mainly in the Mississippi Canyon area. As opposed to the previous evacuation due to Hurricanes Marco and Laura, Rystad expects this situation to last for a couple of days before redeployment and restart begins. The firm’s current estimate for the total outage associated with the Sally weather system is between 3 million and 6 million barrels of oil over approximately 11 days, it said in a release.

Hurricane Sally is expected to make landfall as a Category 1 storm somewhere along the Alabama-Florida coast on Wednesday, according to the US National Hurricane Center (NHC). Sally’s impact will be greater onshore as the NHC forecasts it to be a prolonged storm with “an extremely dangerous and life-threatening storm surge” in coastal areas, with water rising up to 8 feet above normally dry land from southeast Louisiana to the Florida Panhandle. Rainfall totals of up to 30 inches could create significant inland flooding events.

Numerous drilling and production facilities have been shut in as operators began evacuating workers from US Gulf installations late last week As of 11:30 Central time on Tuesday, personnel from 149 of 643 manned platforms in the US Gulf of Mexico have been evacuated, according to BSEE. In addition, operators have evacuated three non-dynamically positioned rigs and two dynamically positioned units have moved off location out of the storm’s projected path.

Anglo-Dutch supermajor Shell said Tuesday it had safely shut in output at its Appomattox asset, with some production curtailment at its Mars, Olympus and Ursa assets. All personnel remain on board.

Chevron evacuated all personnel from its Blind Faith and Petronius platforms and shut-in production at the two facilities. Production at its other Chevron-operated Gulf of Mexico assets remain at normal levels, it said.

The US supermajor added that it has secured its Empire and Fourchon terminals and shut in its Gulf of Mexico pipeline systems.

"Our company is also following our Covid-19 protocols to help ensure the health and well being of our evacuated employees and contractors, as well as the community," Chevron said.

"At our onshore facilities, we are following our storm preparedness procedures and are paying close attention to the forecast and track of the systems."

Non-essential personnel have been evacuated from UK supermajor BP’s Nakika and Thunderhorse platforms and the offshore facilities have been secured, BP said.

"Safety is our top priority and we will continue to monitor weather conditions closely to determine next steps," BP said.