Arieal photo taken on Jan. 3, 2021 shows a view of the Liujiaxia reservoir in Yongjing County, Linxia Hui Autonomous Prefecture, northwest China's Gansu Province. In readiness for potential ice jam floods, Liujiaxia reservoir, a major reservoir on the upper reaches of Yellow River, recently cut its water outflow as required by flood control authorities. (Photo by Shi Youdong/Xinhua)

Arieal photo taken on Jan. 3, 2021 shows a view of the Liujiaxia reservoir in Yongjing County, Linxia Hui Autonomous Prefecture, northwest China's Gansu Province. In readiness for potential ice jam floods, Liujiaxia reservoir, a major reservoir on the upper reaches of Yellow River, recently cut its water outflow as required by flood control authorities. (Photo by Shi Youdong/Xinhua)

Arieal photo taken on Jan. 3, 2021 shows a view of the Liujiaxia reservoir in Yongjing County, Linxia Hui Autonomous Prefecture, northwest China's Gansu Province. In readiness for potential ice jam floods, Liujiaxia reservoir, a major reservoir on the upper reaches of Yellow River, recently cut its water outflow as required by flood control authorities. (Photo by Shi Youdong/Xinhua)

Photo taken on Jan. 3, 2021 shows a view of the Liujiaxia reservoir in Yongjing County, Linxia Hui Autonomous Prefecture, northwest China's Gansu Province. In readiness for potential ice jam floods, Liujiaxia reservoir, a major reservoir on the upper reaches of Yellow River, recently cut its water outflow as required by flood control authorities. (Photo by Shi Youdong/Xinhua)