Famines became common in northern China in the early 17th century because of unusually dry and cold weather that shortened the growing season – effects of a larger ecological event now known as the Little Ice Age. Famine, alongside tax increases, widespread military desertions, a declining relief system, and natural disasters such as flooding and inability of the government to properly manage irrigation and flood-control projects caused widespread loss of life and normal civility. The central government, starved of resources, could do very little to mitigate the effects of these calamities. Making matters worse, a widespread epidemic, the Great Plague in late Ming Dynasty, spread across China from Zhejiang to Henan, killing an unknown but large number of people. The deadliest earthquake of all time, the Shaanxi earthquake of 1556, occurred during the Jiajing Emperor's reign, killing approximately 830,000 people.