Snowfall trends for 1930-31 to 2006-07 for the Midwest region. Trends are given as a percentage of the 1937-38 to 2006-07 snowfall mean per year. Closed circles indicate positive trends while open circles indicate negative trends (Kunkel et al. 2009b). Based on COOP data from the National Climatic Data Center. Only stations with less than 10% missing daily snowfall data for the period 1930-2004 are used in this analysis. Furthermore, the stations shown here passed a stringent quality control analysis using expert judgment. The majority of stations exhibit downward trends. Upward trends tend to occur in northern regions and in Indiana.