We study the annual frequency of occurrence of intense geomagnetic storms (Dst < A100 nT) throughout the solar activity cycle for the last three cycles and ®nd that it shows dierent structures. In cycles 20 and 22 it peaks during the ascending phase, near sunspot maximum. During cycle 21, however, there is one peak in the ascending phase and a second, higher, peak in the descending phase separated by a minimum of storm occurrence during 1980, the sunspot maximum. We compare the solar cycle

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... ibution of storms with the corresponding evolution of coronal mass ejections and¯ares. We ®nd that, as the frequency of occurrence of coronal mass ejections seems to follow very closely the evolution of the sunspot number, it does not reproduce the storm pro®les. The temporal distribution of¯ares varies from that of sunspots and is more in agreement with the distribution of intense geomagnetic storms, but¯ares show a maximum at every sunspot maximum and cannot then explain the small number of intense storms in 1980. In a previous study we demonstrated that, in most cases, the occurrence of intense geomagnetic storms is associated with a¯aring event in an active region located near a coronal hole. In this work we study the spatial relationship between active regions and coronal holes for solar cycles 21 and 22 and ®nd that it also shows dierent temporal evolution in each cycle in accordance with the occurrence of strong geomagnetic storms; although there were many active regions during 1980, most of the time they were far from coronal holes. We analyse in detail the situation for the intense geomagnetic storms in 1980 and show that, in every case, they were associated with a¯are in one of the few active regions adjacent to a coronal hole.