Strong IOD events tend to occur roughly every 10 years. The reasons for this are only being investigated. The countries that are strongly affected by IOD are those in the eastern Indian Ocean (Indonesia to Australia) and equatorial Eastern Africa, where IOD leads to severe lack of rainfall. Moderate impacts are found over portions of India up to southern Iran. We have also found that IOD can lead to excessively warm (southern hemisphere) spring seasons over central portions of South America (e.g. Bolivia).