Extreme Precipitation Events, Impacts, Trends and
Projections for Indiana (227)
Samuel Lashley, National
Weather Service, Syracuse, IN
Abstract:
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.