Just last week we were talking about fall temperature and precipitation trends. Now we’re turning our attention to snow, specifically lake-effect snow as the Great Lakes snow season gets underway. Though it’s a fairly regional phenomenon, lake-effect snow isn’t beyond the reach of climate change.
One might think that there would be less snow in a warming world, but that is not the case for lake-effect snow. In fact, during the period from 1931-2001, there's been a noticeable upward trend in the amount of lake-effect snow falling each year.
Lake-effect snow is created when cold air swoops over the warmer water of the Great Lakes, which hold heat longer than the atmosphere. Water quickly evaporates from the lakes and then falls as snow (if temperatures remain low enough) as winds put it onshore. From 1979 through 2006, the Great Lakes’ surface temperature has warmed 4.5°F. That corresponds with decreased winter ice cover on the lakes. Observations dating back to 1850 also show lake ice forming later and dissipating earlier. So, more exposed and warmer water are supporting more lake-effect snow.
These conditions mean more lake-effect snow is likely for the near future. However, with winter temperatures projected to keep rising across the region, fewer days below freezing (particularly along the Southern Great Lakes) could reverse that trend by the end of the twenty-first century.