Residents boarded up windows, farmers hurriedly harvested vegetables and tourists vacated hotels in eastern Taiwan on Saturday as the island braced for its first typhoon this season.

China and Taiwan warned that Typhoon Fanapi was strengthening before its expected landfall on Sunday on Taiwan’s eastern coast.

Taiwan issued an alert that heavy rains and mudslides were possible and warned ships to expect dangerous sea conditions. The government ordered fishing boats to return to their docks.

Interior Minister Chiang Yi—hua said authorities would evacuate villagers later Saturday from mountainous regions prone to landslides.

Authorities released water from a reservoir to allow more room for the expected torrential rains to gather, Mr. Chiang said.

Taiwan’s Central Weather Bureau said the typhoon was expected to pack winds of between 96 and 110 miles per hour (155 and 177 kph) at landfall.

Officials said tourists vacated hotels in Hualien in eastern Taiwan where Fanapi was expected to land, while residents boarded up windows and piled sandbags at their doors.

In Keelung city in northern Taiwan, fishermen watched the overcast sky after docking their boats.

China’s National Meteorological Centre said Fanapi could be the strongest the country has seen this season. It was expected to hit China’s eastern provinces of Guangdong and Fujian on Sunday night or Monday morning.

Fanapi would be the 11th typhoon to hit China this year. Seasonal flooding in China has been the worst in a decade.

Flooding from Typhoon Morakot killed 700 people in August last year in Taiwan’s worst storm in half a century.

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