Trend Reversal in Lake Michigan Contribution to Snowfall
One of the most notable ways the Laurentian Great Lakes impact the region’s climate is by augmenting snowfall in downwind locations during autumn and winter months. Among many negative consequences, this surplus of snow can cause substantial property damage to homes and can escalate the number of traffic accident-related injuries and fatalities. The consensus among several previous studies is that lake-effect snowfall increased during the 20th Century in various locations in the Great Lakes region. The goal of the present study is to better understand variability and long-term trends in Lake Michigan’s lake-contribution snowfall (LCS). LCS accounts for both lake-effect and lake-enhanced events. Additionally, this study updates findings from previous studies using snowfall observations found by a previous study to be appropriate for climate studies. The present study demonstrates that considerable variability exists in 5-year periods of LCS east and south of Lake Michigan from 1920 to 2005. A general increase in LCS was found from the early 1920s to the 1950–1980 period at locations typically downwind of the lake. Thereafter, LCS decreased through the early 2000s indicating a distinct trend reversal not reported by earlier studies. The reasons for this reversal are unclear. However, LCS trend reversal is consistent with observed increasing minimum temperatures during winter months after the 1970s. LCS and minimum temperature trends are related via teleconnections to recent polarity transitions of the Arctic Oscillation and North Atlantic Oscillation.
lake-effect snow, snowfall trends, climate change, Lake Michigan, teleconnections, scale interactions
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign