It seems as though summer was only a couple of weeks ago, but this past week saw the first big storm of the winter. Buffalo, New York, was covered in 90 inches (about 2.25 metres) of snow, leaving people stranded in their cars and volunteers scrambling to dig the city out from under the frozen blanket.
What is it that makes cities like Buffalo so prone to deep snowfalls? What causes the "snow belts" around the Great Lakes? It's actually a kind of snow fall called "lake effect."
The cold Arctic winds come from the north west, blowing southeast over the waters of the lake. These kind of snowfalls happen early in the winter season, before the lake has frozen. Being relatively shallow, Lake Erie, Buffalo's lake, usually freezes over by January or February, so its storms occur early in the season. When the lake is frozen, water can't evaporate and fall as snow. Lakes Ontario, Superior, Michigan, and Huron are deeper and therefore more prone to these kinds of snowfalls throughout the winter. because they don't freeze over, although last year's Polar Vortex changed this, freezing even these lakes.. Especially in late autumn and early winter, the lake water is relatively warm and when the cold wind blows over the long expanse of lake, convection draws the water up into the atmosphere. It hits the colder air and turns to snow. As the wind blows toward shore, the snow falls. And falls, particularly on the south shore. The east sides of the Great Lakes tend to be hilly as well, creating terrific ski conditions in certain areas of Ontario and upper New York state.
The record for snowfall in a 24-hour period is held by Silver Lake, Colorado, where 76 inches fell in a day in 1921. Toward the eastern seaboard, the Tug Hill plateau in New York is one of the snowier places in North America, frequently sustaining record snowfalls.
Climate change will, of course, affect our snowfall patterns. If the large Great Lakes stay unfrozen throughout the winter, then more water will be available to evaporate into the atmosphere and return as snow. This will have implications for our cities' snow removal budgets. And then, the more snow there is, the more spring meltwater is running into our creeks and rivers, increasing the risk of springtime floods.
If winter would stay winter, and stay frozen, that would be one thing, but the cycle of freezing and thawing can wreak havoc on the forests that ring the Great Lakes. The maple and birch trees in particular rely on the snow pack to protect their roots. Their sap begins to flow when spring brings warm days and cold nights. Early thaws combined with long periods of freezing temperatures, will definitely have an adverse effect on our sugar bushes.
Winter is back, like it or not: lace up your Sorels, grab your (faux!) fur trapper hat, and get ready. The Ice and Snow Storms cometh....! But, let's hope the Polar Vortex stays at home for now....