MEXICO CITY — The first hurricane of the season formed off Mexico’s southern Pacific coast Sunday and rapidly gained power ahead of an expected strike along a stretch of tourist beaches and fishing towns.

Agatha could make landfall as a Category 3 hurricane Monday afternoon or evening in the area near Puerto Escondido and Puerto Angel in the southern state of Oaxaca – a region that includes the laid-back tourist resorts of Huatulco, Mazunte and Zipolite.

At midafternoon Sunday, the recently formed hurricane had maximum sustained winds of 110 mph and was centered about 185 miles southwest of Puerto Angel, the U.S. National Hurricane Center said. It was heading to the northeast at 1 mph.

The center said Agatha could have winds of 120 mph when it makes landfall.

A hurricane warning was in effect between the port of Salina Cruz and the Lagunas de Chacahua.

The civil defense office in Oaxaca said the hurricane’s outer bands were already hitting the coast. The office published photos of fishermen hauling their boats up on beaches to protect them from the storm.

Municipal authorities in Huatulco ordered “the absolute closure” of all the resort’s beaches and its famous “seven bays,” many of which are reachable only by boat. They also closed local schools and began setting up emergency storm shelters.

To the east in Zipolite, long known for its clothing-optional beach and bohemian vibe, personnel at the small Casa Kalmar hotel gathered up outdoor furniture and put up wooden storm shutters to prevent strong winds from blowing out glass windows and doors.

“The biggest worry here is the wind,” hotel manager Silvia Ranfagni said.

With only one guest – and plenty of cancellations due to the hurricane – Ranfagni planned to ride out Agatha at the property, which is several blocks from the beach.

“I’m going to shut myself in here with my animals,” she said, referring to her dog and cats.

The government’s Mexican Turtle Center – a former slaughterhouse turned conservation center in Mazunte – announced it was closed to visitors until further notice because of the hurricane.

The U.S. National Hurricane Center warned of dangerous coastal flooding, as well as large and destructive waves near where Agatha makes landfall.

The storm was expected to drop 10 to 16 inches of rain on parts of Oaxaca state, with isolated maximums of 20 inches, posing the threat of flash floods and mudslides.

Because the storm’s current path would carry it over the narrow waist of Mexico’s isthmus, the hurricane center said there was a chance the storm’s remnants could re-emerge over the Gulf of Mexico.