The hypothesis that rainfall might be a case of self-organized critica
l dynamics is tested using long-term data sets from weather stations a
round the world. It is found that the distribution of droughts in semi
-arid regions obeys indeed a clear-cut power law. The statistics for r
ain intensity, on the other hand, exhibits two distinct scaring regime
s. (C) 1998 Elsevier Science B.V. All rights reserved.