Seasonal Distributions of Heavy Rainfall (p. 25)----Summer is the Time

"Background---

"In the design of some hydrological systems or structures, it is pertinent to know the seasonal characteristics of heavy rainstorm as well as the frequency distribution of maximum storm rainfall amounts for various storm durations. For example, when the soil is near saturation, a spring storm of inensity equilavent to a 5 Years recurrence interval may have different consequences that had the same storm occured in a drier summer month. Winter storms, while generally producing less precipitation than summer storms, can be devastating if they occur over frozen ground. With or without snow cover, these winter starms can cause rapid flooding."

Two points here: Seasonal variation makes a difference---and summer is the time for the Midwest where we have the most rain. Second--antecedent soil condition makes a difference. If the soil is saturated or the soil is frozen, an event which might be considered a 5 year event could be devastating if not properly planned for with respect to runnoff.

Read on past 25 for the full scoop. Click on the post.