They lived in tropical areas that experienced periodic drought.
Finally, periodic drought common to southern Madagascar can impact populations already in decline.
Francisco Dumont suffers from periodic drought and poor highway communications.
The Volga basin is subject to periodic droughts that can sometimes last for several years.
But rapidly growing cities have increasingly been puckered by periodic droughts.
From about 900 to 1300, scientists say, periodic drought in the West was the norm.
The climate is semi-arid and the region suffers from periodic drought.
Most villagers however, still mainly survive by agriculture and face the risk of periodic drought.
This year, with the economy depressed by one of the country's periodic droughts, the market has been mainly flat.
The nation of Botswana has periodic droughts which make agriculture difficult.