KIM HARRISBERG WHEN Nozipho Sithole closes her eyes to sleep, she still hears the screams of her neighbour's two young children as they were swept away by the floodwaters that killed hundreds of people in South Africa last month. Like Sithole, many of those living in a community hall in the eastern city of Durban are haunted by what they saw, and what they lost. Muffled sobs echo through the shelter at night, she said. "The night the floods started, the sand looked like it was boiling from the water, the whole house was moving," said the 35-year-old, who gave…