Debris flow traces at Jilong port are as high as a 20-story building; rescuers have searched a 40,000-square-meter area twice. What are the remaining challenges in the rescue?

吉隆口岸泥石流痕迹有 20 层楼高，救援人员已把 4 万平的区域搜寻了两遍，目前救援还有哪些难点？

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