Hurricane Alex strengthened in the Gulf of Mexico early on Wednesday and was expected to make landfall later in the day but skirt Mexican oil rigs and U.S. oil fields, alleviating concerns in crude markets.

The first named storm of the Atlantic season became a Category 1 hurricane late Tuesday night as it slowly moved west toward northern Mexico where it was expected to drop as much as a foot of rain.

While the storm was forecast to miss major oil drilling sites, rough seas and rain were already hampering efforts to control damage left by an ongoing spill from the major leak at a BP Plc facility south of Louisiana.