The present study involves the daily precipitation data of the moonsoon season (June-September) for the period 1940-1990. The data has been characterised into 11 flood papers. A test of significance at 5% level was carried out using student 't' distribution . Stations qualifying the significance test are considered here. Each station has been studied individually in every flood year with rainfall variability/distribution ascertained per year. As observed, flood occurs occurs mainly due to the tropical disturbances, like the monsoon depressions, cyclonic storms, low pressure systems (monsoon lows) passing from the neighbouring seas. i.e. Bay of Bengal and Arabian sea. Average number of low pressure system days are cruciual to the flood years.

Understanding the interseasonal and interannual variability of the moonsoon rainfall, daily and seasonal anomalies has been gauged by using the Empirical Orthogonal Function (EOF) analysis. Further,EOF analysis was used to find out the nature of rainfall distribiution patterns in flood years. This technique thus identifies the spatial and temporal pattern characteristics of possible physical significance.