Disaster looms in East Africa

There have been several consecutive seasons with above average rainfall in East Africa, an unusual event in this drought prone area. Then everything changed. The abundant moisture of past seasons exited the region resulting in drought conditions across Ethiopia, Somalia and Kenya. The October to December rains, known as the Deyr Rains, have failed. Pasture for cattle to graze on is running out, and crops that were planted in the hopes of a wet season have barely broken the surface, if they were lucky enough to even germinate. Many areas, especially in Somalia and Ethiopia, have received no rain at all. The prognosis isn't good. Little to no rain is coming to end the drought in the next month and a half. What happened? What went wrong? ...and when will it end?