Extreme Precipitation Events, Impacts, Trends and Projections for Indiana (227)

Samuel Lashley, National Weather Service, Syracuse, IN



The National Weather Service (NWS) is working with core partners to build a Weather Ready Nation (WRN) that is prepared for future weather extremes. Recent years have seen numerous record breaking heavy rainfall events across the state of Indiana along with devastating flooding, including the unprecedented rainfall and flooding event of February 2018. Core partners and the public in general have recently started asking questions concerning a developing perception that the frequency of these intense and record breaking rainfall events are increasing. Understanding past events and studying climatological trends in local rainfall data is critical in effectively communicating and putting into perspective future impacts, trends and projections of heavy rainfall events.

This presentation will review several extreme rainfall events that have occurred across Indiana along with their impacts on local communities and infrastructure. Precipitation data and trends from NWS climate stations across Indiana dating back more than 100 years was analyzed to determine if these events are increasing. An increased frequency in the number of defined heavy rainfall events as well as an increased number of daily events greater than two and three inches were observed, especially over the most recent 30 years. Climate analysis tools were also used to diagnose an increasing climatological rate of change in annual precipitation, ranging from just over one and a half inches across northwest Indiana to more than two and a half inches across southeast Indiana. These results support future climate projections for precipitation trends across Indiana which will also be shown. Results of this study should aid the NWS and core partners in putting recent precipitation trends into historical perspective while also explaining what projections of increased rainfall will mean for Indiana.