BBC: Some 57,000 people have been forced from their homes because of dramatic floods in south-western Sudan over the past month, health officials say. Heavy rains have left Aweil, the main town of Northern Bahr al-Ghazal province, largely under water. A BBC correspondent says the floods pose another challenge to the already delayed voter registration. Southern Sudan is voting on whether to secede from the north in a referendum in January. Challenge The BBC’s …