The US National Hurricane Center said Blas had maximum sustained winds of 140 mph by mid-afternoon. It was centered about 210 miles (340 kilometers) south-southwest of Manzanillo and it was heading west-northwest at a speed of 8 mph (13 kph).
Forecasters expected Blas to begin to weaken Friday night as it stayed above open water and moved further into the Pacific. But they added that the hurricane brought dangerous surf to the Pacific coast.
The harbourmaster of Puerto Escondido in the Mexican state of Oaxaca announced that the port will be closed to shipping from Wednesday afternoon.
The region southeast of Puerto Escondido was ravaged when Hurricane Agatha made landfall near Puerto Angel on May 30 with maximum sustained winds of 165 km/h. Authorities said floods and mudslides caused by Agatha’s heavy rains have killed at least nine people, and five others are missing and presumed dead.
The local military commander, Antonio Ramírez Escobedo, told the national newspaper Milenio that 17 towns or villages in the mountainous region were still closed off from the road due to collapsed bridges, landslides or downed trees.
He said more than 100,000 people in 119 communities suffered damage to their homes.
The federal interior ministry on Tuesday declared a state of emergency in 38 townships, making them eligible for priority relief efforts.