This winter, areas downwind of the Great Lakes have received enormous amounts of lake effect snow. Can climate change be occurring when storms are piling up record snow?
Yes – in fact, this phenomenon is entirely consistent with climate change models.
Lake-effect snow develops when cold air moves over a relatively warm large body of water. In response to increased levels of carbon dioxide in the atmosphere, Great Lakes temperatures have been slowly rising in recent decades, and last autumn’s Great Lakes water temperatures were among the highest recorded for that time of year.
As cold air passes over the lakes, it absorbs warmth and moisture from the water, transferring these elements to the lower atmosphere. This air rises and condenses into clouds, which can develop into narrow bands that may produce intense snowfall rates of two to three inches per hour. Areas within these bands can be buried in snow, while little to no snow may fall just a few miles away.
Some spots in the lake-effect zones, downwind of the Great Lakes, have seen more than five feet of snow already this winter. This is the result of unusually high lake surface water temperatures, which set up sharper contrasts with Arctic winds rushing over the lakes.
A November lake effect outbreak dumped 23 inches of snow on Sault Ste. Marie. The same outbreak brought 40 inches of snow to parts of the state of New York. Lake effect snow has contributed significantly to much higher snowfall totals compared to last year in northern Michigan.
As of Monday, January 27, Traverse City had received over 80 inches of snow this season, compared to approximately 60 at the same time last year. Gaylord’s snowfall total had risen from approximately 130 inches compared to approximately 95 at the same time last year. Houghton, in the Keweenaw Peninsula, is a bullseye for lake effect snow. It had received 147 inches of snow compared to 97 at the same time a year ago.
“Warmer Great Lakes surface water temperatures and declining Great Lakes ice cover have likely driven the observed increases in lake-effect snow,” says a climate change adaptation team of the National Oceanic and Atmospheric Administration, which predicts further increases in such snow. And areas in the southern Great Lakes region may experience increased lake-effect rain.
By the way, lake-effect snow does not raise Great Lakes water levels. It is essentially recycled water, because the moisture comes from the Great Lakes and then returns to the lakes as it melts. The remainder will evaporate or percolate into groundwater.
