The distribution of rainfall in the Sahel region is uneven. The rainfall in the region has been below average since 1970. The Sahel is becoming drier on the whole. The problem of drought affects most of the countries in the Sahel. As a result, crops and animals die. There is no vegetation to protect the soil, which is then removed by flash floods and strong wind. This leads to soil erosion. Finally, the desert spreads towards the surrounding areas.