More on the La Porte Anomaly: A Review

Abstract

Abstract The anomalous behavior of the precipitation in northwestern Indiana (the La Porte anomaly) since the late 1930s has been extensively studied and debated. Local records suggested an upward shift in warm season rainfall, thunderstorms, and hail during the 1935–65 period. The possible causes for this included changed station exposure, a poor observer, urban influences on the atmosphere due to nearby Chicago, and/or shifts in the general circulation patterns. Most debate has centered on the observer error versus urban effects explanation, but the La Porte anomaly has become a cause celebre in the interwoven areas of climate change, air pollution, weather modification, and the quality of climatic records. A variety of recent studies of rainfall conditions and their areas of impact (streamflow, crop yields, and hail losses) show that the anomaly in the La Porte area began to shift locale in the 1950s and then disappeared in the 1960s. Taken in totality, it seems likely that the anomalous precipitation ...