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Directions: Record your answers in the spaces provided in your answer booklet.
Some questions may require the use of the Earth Science Reference Tables.
Base your answers to questions 1 through 4 on the magazine article and diagram below.
Lake
-Effect Snow
During the cold months of the year, the words “lake effect” are very much a part
of the weather picture in many locations in New York State. Snow created by the lake
effect may represent more than half the season’s snowfall in some areas.
In order for heavy lake effect snow to develop, the temperature of the water at the
surface of the lake must be higher than the temperature of the air flowing over the water.
The higher the water temperature and the lower the air temperature, the greater the
potential for lake-effect snow.
A lake
-effect storm begins when air flowing across the lake is warmed as it comes
in close contact with the water. The warmed air rises and takes moisture along with it.
The moisture, which is water vapor from the lake, is turned into clouds as it encounters
much colder air above. When the clouds reach the shore of the lake, they deposit their
snow on nearby land. A typical lake-effect storm is illustrated in the diagram below.
The area most likely to receive snow form a lake is called a “snowbelt.” Lake
Ontario’s snowbelt includes the counties along the eastern and southeastern ends of the
lake. Because the lake runs lengthwise from west to east, the prevailing westerly winds
are able to gather the maximum amount of moisture as they flow across the entire length
of the lake. There can be lake-effect snowfall anywhere around the lake, but the heaviest
and most frequent snowfalls occur near the eastern shore.
In parts of the snowbelt, the lake effect combines with a phenomenon known as
orographic lifting to produce some very heavy snowfalls. After cold air has streamed over
the length of Lake Ontario, it moves inland and is forced to climb the slopes of the Tug
hill Plateau and the Adirondack Mountains, resulting in very heavy snowfall.