MEXICO CITY >> Hurricane Agatha, the strongest hurricane on record to make landfall in May in the eastern Pacific, swept ashore on a stretch of tourist beaches and fishing towns today, then weakened moving inland over the mountains of southern Mexico.

Torrential rains and howling winds whipped palm trees and drove tourists and residents into shelters as Agatha pushed onto a coastal region that is sparsely populated except for a handful of small communities along the shore.

Oaxaca state’s civil defense agency showed families hustling into a shelter in Pochutla and a rock and mud slide that blocked the highway between that town and the state capital.

Agatha made landfall about 5 miles (10 kilometers) west of Puerto Angel in the late afternoon as a strong Category 2 storm, with maximum sustained winds of 105 mph (165 kph). But it quickly began losing strength as it moved inland.

Late Monday, it was downgraded to a tropical storm, with maximum sustained winds of 70 mph (110 kph). The U.S. National Hurricane Center said Agatha was expected to dissipate overnight, but warned that the system’s heavy rains still posed a threat of dangerous flash flood.

Earlier in the day, wind, heavy rain and big waves lashed the beach town of Zipolite, long known for its clothing-optional beach and bohemian vibe.

“There is a lot of rain and sudden gusts of strong wind,” said Silvia Ranfagni, manager of the Casa Kalmar hotel in Zipolite. Ranfagni, who decided to ride out Agatha at the property, said, “You can hear the wind howling.”

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In the surfing town of Puerto Escondido, people took shelter and put up plywood to prevent windows from breaking in the strong winds.

The government’s Mexican Turtle Center — a former slaughterhouse turned conservation center in Mazunte — closed to visitors because of the hurricane.

Agatha formed only on Sunday and quickly gained power. It was the strongest hurricane on record to make landfall in May in the eastern Pacific, said Jeff Masters, meteorologist with Yale Climate Connections and the founder of Weather Underground.

He said the region’s hurricanes typically get their start from tropical waves coming off the coast of Africa.

“Since the African monsoon typically does not start producing tropical waves until early- or mid-May, there simply aren’t enough initial disturbances to get many eastern Pacific hurricanes in May,” Masters wrote in an email. “In addition, May water temperatures are cooler than they are at the peak of the season, and wind shear is typically higher.”

The U.S. National Hurricane Center said Agatha could drop 10 to 16 inches (250 to 400 millimeters) of rain on parts of Oaxaca, with isolated maximums of 20 inches (500 millimeters), posing the threat of flash floods and mudslides. It said lesser amounts could fall in adjacent states to the east and northeast.