Desertification: when the top layer is washed out only sub-soil remains which is unsuitable for growing plants.
Landslides in hilly areas: hilly areas or rocky mountains that are affected by heavy rains will have loose soil that causes landslides in hilly areas.
Flash floods: barren hills with sparse vegetation cannot absorb much rainwater and thus cannot keep the soil intact. So, heavy rains result in rapid movement of water resulting in flash floods in lower areas causing tremendous losses to life and property.