Johannesburg — Aid workers are sounding the alarm over an intensifying humanitarian catastrophe in Somalia, where officials are expected to soon declare the second famine in just over a decade. Aid workers tell CBS News that rampant drought in the east African nation has already sparked a mass-migration of desperate families who can't feed their children. Many are showing up too late at makeshift camps for help, and the conditions are expected to get worse over the winter. In early October, United Nations humanitarian chief Martin Griffiths said he had "no doubt that we are seeing famine on our watch in Somalia." A formal famine declaration comes when a region or nation meets certain proscribed criteria on mortality rates, insecurity and other metrics. It doesn't trigger any legal response, but it will often galvanize the international community to help more urgently. Doctors on the ground tell CBS News they're expecting a formal declaration of famine in some Somali regions next month,