Cold dry air from Canada moving across the relativity warmer waters of the Great Lakes produce a fair amount of our precipitation over Southwestern Pennsylvania at this time of the year.

We also get an occasional shower in our warmer months as a result of Lake Effect but its wintertime that can produce some heavy snows.

As you travel north the effects of this snow-making machine increase and areas just a few miles south of Lake Erie and Lake Ontario occasionally see some impressive snows.

Weather folks tell us that a difference of at least 23 degrees in the temperature of the water and the air at the 5,000-foot level is needed to produce this snow. As the cold dry air flows over the lakes it picks up moisture and forms the clouds and snow. The moisture laden air then rises over the hills once it hits land and the snow begins.

It is interesting to note that areas immediately along the lake shore usually receive less snow as the hills are needed to produce the maximum snowfall totals. Erie receives an annual snowfall average of 80 inches while nearby Corry, Pa. sees 122 inches and Meadville receives on average 111 inches.

Even areas far away from the lakes can get a fair amount of Lake Effect snow. Nearby Seven Springs with their elevation close to 3,000 feet above sea level also gets 125 inches of snow on average.

Of course, not all of our winter snows are induced by the lakes but snowfall totals would be substantially lower if we did not have the Great Lakes. The ingredients for good snowfalls are the cold, dry air, the warmer waters and then the elevation lifting this moisture and depositing it downwind of the lakes.

In our own area we certainly see the effect of this with 88 inches of snow on average at Chalk Hill, a mountain elevation, while nearby Uniontown just gets 38 inches per season on average. Eleven out of the 15 snowiest cities in the United States are located downwind from the Great Lakes. Terra Alta in West Virginia and Oakland, Md., also due to their elevation and the effect of the Lake, receive 158 and 96 inches on average each winter.

The best time for Lake Effect snow is in late fall and early winter when the lakes are not yet frozen over with ice, and the water and air temperatures are at their greatest difference.

Lake effect snows can still occur in later winter but are usually of lesser intensity. They also like to form in narrow bands and sometime these bands are only 10 to 20 miles wide. Thunder and lightning can also occur in some of the more intense bands. Many times cities will see copious amounts of snow on one side of town while small amounts or no snow at all will fall just a few miles away.

In November of 2014 a very intense but narrow band of snow set up shop just south of the city of Buffalo, N.Y. Three feet of snow fell during the first 12 hours of the storm and by the time the storm dissipated 65 inches of snow brought a halt to everything.

The unofficial world record for snow occurred at Montague, N.Y. when 77 inches of snow fell in 24 hours during a Lake Effect snow event in January of 1977.

Last year, with a mild winter and the lakes not frozen, Carthage N.Y. received 50 inches of snow on the last two days of February. This past week areas just east of Uniontown received several inches of snow as colder dry air crossed the warmer waters of Lake Erie and then was lifted by our mountains and deposited on areas like the Summit, Chalk Hill and Farmington.

There is something so beautiful and peaceful about the first snowflakes of the season.

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