Twelve Feet of Snow, but Why All in One Place?

Feb. 13, 2007 — -- The snow's been so deep that ...

There's been so much of it that ...

Actually, there's been so much snow in Oswego County, N.Y., on the eastern end of Lake Ontario, that people are running out of ways to describe it.

"In all my life, I mean my entire life combined, I've never seen this much snow at once," said Jim Bevridge, a visitor who drove up from Maryland for a long weekend of snowmobiling.

Unofficially, the town of Redfield reported 12 feet, 2 inches of snow since Feb. 3. Other towns in Oswego County have had nine to 10 feet.

But why there? Why not two counties away? Why, for that matter, is there more snow in Redfield than in parts of Canada, several hundred miles to the north?

Oswego County is at the receiving end of what's called lake effect snow. It can happen, under the right circumstances, almost anywhere on the planet, but in winter the Great Lakes create almost the perfect mix.

Lake effect snow forms when moisture, evaporating from the surface of a body of relatively warm water, is picked up by cold air blowing over it. In cold months the wind, heavy with humidity, dumps the moisture onshore in the form of snow.

The effect is most pronounced on the shores of a large lake, as the prevailing winds travel from one side to the other.

It explains, for instance, why the Wasatch Mountains of Utah are a skier's paradise. They're fed almost year-round by winds blowing from the west over the Great Salt Lake, which is too briny to freeze.

Likewise, Benton Harbor, Mich., on the eastern shore of Lake Michigan, gets far more snow than Chicago, directly across from it.

But the U.S. champion seems to be at the eastern end of Lake Ontario, an area of upstate New York known as the Tug Hill Plateau, which includes Oswego County.

Redfield, positioned perfectly on the plateau a few miles from Lake Ontario's end, routinely averages 270 inches of snow a year -- about 22 feet, all told. The towns of Montague and North Osceola often get more than 300 inches' worth.

They're used to it. In winter this area is a haven for lovers of snowmobiling. But even the locals will concede this month has been a bit much.