Many of the main roads running through Unity State are now completely submerged, yet the traffic remains. There are no cars, just people, some of whom swim, others wade, pushing their way through the heavy silt-laden water. This deluge, which is the worst in 60 years according to the UN, has swallowed not only the very roads that people here need to escape, but also their farms, homes and markets. For years, South Sudan has been experiencing wetter-than-normal wet seasons, while its dry seasons are becoming even drier. The rainy season has ended, yet the water that has accumulated over months has yet to recede. South Sudan is one of many places in the world struggling with this twin problem of drought followed by extreme rainfall, which together create prime conditions for devastating floods. More than 850,000 people have been impacted by the floods, the UN agency coordinating the relief effort there told CNN, and some 35,000 of them have been displaced. Remote towns like Ding Ding now sit largely abandoned. The traditional straw roofs of many homes here peak above the waterline, their walls still submerged.