THE ZONES OF SEVERE RAINSTORM ACTIVITY OVER INDIA

Examination of rainstorm data has shown that the Indian area has exper ienced about 97 severe rainstorms during the last 110 years. It has be en seen also that the heavy-rain centres of these severe rainstorms ha ve certain preferred areas or zones where they have occurred quite fre quently. These zones have been demarcated and it has been found that t here are four such plain-area zones in the country. It is felt that th ese zones broadly demarcate or limit the areas where transposition of rainstorms can be attempted using the rainstorm of that particular zon e only in order to obtain design storm estimates for the design of spi llway capacities of dams. Knowledge of these rainstorm zones can be he lpful in forecasting rainfall and floods associated with cyclonic dist urbances and for preparation of generalized charts of probable maximum precipitation.