ENSO Top Meteorological Drought Defined Drought is a period of insufficient water initiated by reduced precipitation. The impacts of drought on crops and society are crititcal but not easily quantified. While crops may be damaged by lack of precipitation and high temperatures in just a few days, such short periods are not considered to be meteorological droughts. A three-month period is defined by the American Meteorological Society to be the shortest period that can be defined as a drought. Since Ethiopia and Eritrea are in the tropics, physical conditions and variations in altitude have resulted in a great diversity of climate, soil, and vegetation.
Rainfall is seasonal, varying in amount, space, and time.
There is a long and heavy summer rain, normally called the big rain or keremt , which falls from June-September. It is followed by the baga hot, dry period from October through February. In some areas there are short and moderate spring rains in March and April known as the little rains or belg . These rainy periods correspond to Ethiopia's primary and secondary agricultural seasons, known as the meher and belg . In spring, a strong cyclonic center develops over Ethiopia and Sudan.