Last week more than 65 inches of snow blanketed northeastern PA in less than 48 hours, causing traffic problems on the roads, shoveling hassles, and some degree of astonishment for everyone within the localized area around Lake Erie. “Lake effect” snowfalls like this one are becoming more frequent and intense as the climate warms, and as this happens, those who live in affected areas are taking steps to learn more about what this phenomenon means and how it works.
When cold winds blow from inland areas toward the coast, they sometimes blow over large bodies of slightly warmer water like the Great Lakes. When the conditions are in place—cold air, warm water, and appropriate wind speeds—the warm water of the lake condenses and rises up into a cloud. The cold wind then turns the condensed water into snow and drops the snow in heavy masses onto the land just downwind of the lake. Satellite images taken above the Great Lakes sometimes show distinct bands of lake effect snowfall appearing downwind, and the areas just south and east of the lakes are known for these highly localized blizzards.
In human terms, this combination of warm water and cold wind sometimes brings the familiar scene of a bundled-up person with snow shovel in hand, digging out a buried car and wondering if ‘global warming’ is some kind of paradox. How can a ‘warming’ planet bury said car in bigger and bigger snowfalls every year?
The answer is simpler than some perplexed shovelers might think. It’s so simple it can actually be summed up in one equation: warmer lake water means more condensation, which means more snow.
Unfortunately, this direct correlation can be lost on those who are burdened by the anxieties of the moment. Residents of towns buried in record blizzards aren’t always receptive to lectures and charts that demonstrate the link between carbon output and six-foot snowdrifts. But the link exists all the same, and some predict that water temperatures and corresponding snow totals will rise in the areas around Lake Superior at a steady pace until about 2050.
What will happen after that?
Some climate models suggest that increases in lake effect snowfall will slow as the temperature of the winds blowing across the lake rise and the contrast between cold air and warm water begins to level off. If these predictions hold true, snows will increase for the next few decades and then begin to decrease, in a pattern that may seem out of sync with other charts that show steady shifts in, for example, record summer heat, disappearing sea ice, or population shifts among specific plant, animal and insect species.
As always, we’ll be tracking these changes with interest and looking closely at patterns that may seem counterintuitive or difficult to explain. Join us in our efforts to make sense of the data that accumulates as we move through the unpredictable decades ahead.