Having brought the coronavirus pandemic largely under control, China’s leaders are now struggling with a surge of crippling floods that have killed hundreds of people and displaced millions across the central and southwestern parts of the country. Flooding on the Yangtze River peaked again this week, in Sichuan Province and the sprawling metropolis of Chongqing, while the Three Gorges Dam, 280 miles downstream, reached its highest level since it began holding water in 2003.

This year’s flooding has unfolded not as a single natural disaster, with an enormous loss of life and property, but rather as a slow, merciless series of smaller ones, whose combined toll has steadily mounted even as official reports have focused on the government’s relief efforts. “The Chinese nation has fought natural disasters for thousands of years, gaining precious experience,” the country’s leader, Xi Jinping, declared on Tuesday after a visit to Anhui, another flooded province downstream from the Three Gorges Dam. “We should continue to fight.”

Public appearances in flood-stricken areas by Mr. Xi and China’s premier, Li Keqiang, underscored the severity of the crisis, which has delivered another blow to an economy still struggling to rebound from the pandemic. Mr. Li visited Chongqing, where the Yangtze spilled over its banks for the fifth time this year and, on Thursday afternoon, breached the historical high reached in 1981. The leaders have tried to reassure people that the government was doing everything it could, but some might have doubts.

“I believe that the Chinese public will question Beijing from this year’s continuous natural and man-made disasters, and even question China’s governance model and its effectiveness,” said Wu Qiang, an independent political analyst in Beijing.