Truly extreme lake-effect snows gather their energy from a wide temperature differential between the lake temperature and the air temperature. That temperature contrast produces atmospheric instability—the warm air immediately over the lake wants to surge upward through the colder air on top, bringing with it heaps of evaporated moisture. That moisture is quickly converted to snowfall in massive quantities...As the Great Lakes warm due to climate change, there’s now more evaporation, and more of an opportunity for that drastic water-air temperature difference to manifest itself, especially during the kinds of intense cold air outbreaks that we’ve been seeing seemingly more of over the last few years.