Using rainfall data from 66 stations within the Chira-Piura Project of northwestern Peru, we have prepared an atlas of histograms and contour maps describing the daily rainfall characteristics of the region during El Ni¿o period from November 1982 to June 1983. We have compared these data with those for the same 8-month intervals during the 2 years preceding and following the designated period. Uniquely during the El Ni¿o period, these data often exhibit localized storms of high rainfall intensity (>100 mm/d) which may then disperse over wider areas of the region during the following 2--3 days. The region nearby and to the east of Chulucanas (5.10 ¿S, 80.17 ¿W) appears to be a focal point for the initiation of such events, particularly during the 1983 months of the period. Case studies for a few of the most severe events have been performed and compared with analysis using GOES satellite cloud imagery in conjunction with upper air and surface weather maps, to arrive at a possible scenario for the cause and evolution of such events. Statistically, a high percentage of the storms are found to be multicellular with scale sizes approaching 250 km, with minimum cloud temperatures colder than -60 ¿C, and of durations exceeding 6 hours. Such storm systems are consistent with the extreme and disastrous rainfall events observed from ground stations. The satellite analysis has also permitted us to identify significant storms beyond the range of the ground-based stations during this same time period, demonstrating the complementary value of satellite coverage for developing a more comprehensive view of the processes in effect. ¿ American Geophysical Union 1987