Weather Week: The connection between climate change and lake-effect snow

Weather Blog

ROCHESTER, N.Y. (WROC) — The average temperature in Rochester has increased about one degree Fahrenheit since 1930. While this may seem small, scientists say this is one of the many signs of climate change that will continue to impact weather locally for years to come. 

While the science says we are already seeing worsening droughts and heavier rain events, there is still some question about how lake-effect snow will be impacted by a warming climate. 

Major scientific reports have come out on impacts climate change is having on the Great Lakes, but to figure out the exact impact on lake-effect snow, it is important to first separate weather and climate.   

Think time scales, says Scott Rochette, professor of meteorology at the College at Brockport. “Day-to-day weather is what you get,” said Rochette. “Climate is what you expect. Even though the climate is getting warmer over time, that means the average temperature is getting warmer, it doesn’t mean we aren’t getting cold air anymore, obviously.”  

Gradual atmospheric warming will not stop major cold snaps, but it will warm the lakes. In fact, according to NOAA, Lake Ontario has warmed over two degrees since 1995. That warming can contribute to lake effect.  

“You need relatively warm water and you need very cold air,” said Rochette. Water holds heat well and has a higher specific heat. That means temperatures change slower. Essentially it remains warmer, longer. We will still get cold snaps so the air temperature will be cold, and we can get lake effect snow. 

The second factor is ice cover. When ice covers the lake, like on Lake Erie, the moisture source is gone. A warmer climate could mean a longer ice-free season. “If the lake is more open for a longer period of the year, than you have the potential for the lake effect season going longer, and warmer water longer means better potential for lake effect,” said Rochette. 

The Rochester airport since World War II has seen an increase in annual snowfall of more than a foot. There is high variability between years, but this does this support other studies that have looked at locations all across the Great Lakes. 

This means that in the short term there could be more lake-effect snow across the Great Lakes. “By short term we’re talking about climate short term, 10,20,30 years, we might see more lake effect snow in a longer season.” 

Wind direction is another important factor in who sees more lake effect snow. No connection has emerged with climate change. 

As far as the longer-term outlook as temperatures continue to warm, any snow will become less prevalent and more rain will fall during the winter months. Much of this will depend on how greenhouse gas levels trend over the next century. 

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