Energy companies on Monday began evacuating offshore oil platforms as the 25th named storm of the year formed in the Caribbean and was forecast to move into the Gulf of Mexico and threaten the Gulf Coast this week.

Tropical Storm Delta was expected to strengthen as it crosses the warm waters of the Gulf of Mexico midweek and to approach the northern Gulf Coast as a category 1 hurricane with up to 105 mile per hour (194 kilometers per hour) winds, the National Hurricane Center said.

BP and BHP began evacuating non-essential personnel from their offshore platforms, the companies said. BHP also plans to shut production at its facilities by Wednesday.

Occidental Petroleum, the third largest offshore producer by volume, said it was taking steps to protect its people and facilities. Royal Dutch Shell said it was monitoring the storm. Offshore production in U.S. Gulf of Mexico accounts for 17% of total U.S. crude oil production and 5% of total U.S. dry natural gas production.

NHC’s storm track has Delta to move up the central Gulf of Mexico and making landfall on the central Gulf Coast. Louisiana Governor John Bel Edwards urged the state’s residents to prepare for the storm. Southwestern Louisiana was hit in August by Hurricane Laura’s 150 mph winds and is still recovering.

Delta is the 25th named storm of the Atlantic hurricane season, which runs from June 1 to Nov. 30. This year’s season has been unusually active, with more than double the average number of named storms and eight weeks ahead of it.