For most of the year the Gash river running through Kassala is not a river at all but a broad pale sand wash a couple of hundred metres wide. In the cool of the late afternoon it becomes one of the social spaces of the city — pickup football matches, kids practising karate, families walking, hawkers selling roasted nuts and tea.
From late June into September, when the rains fall over the Eritrean highlands a hundred kilometres east, the Gash arrives in flood — a brown, fast-flowing river that has carved away parts of the banks more than once in living memory. The bridges fill with people watching the water and with daredevil children jumping in from the rails. It is one of the great Sudanese seasonal spectacles.
The flood lasts only weeks, then the river soaks back into the sand. Cross to the other bank — quieter, mostly residential, with the predominantly Hausa Gharb el-Gash quarter and its evening agashe (skewered meat) stalls, and the old British-era railway buildings of Sikka Hadeed beyond.