Snow

(This column first appeared in the January 19, 1999 Buffalo News.)

    Now that a truck plows our driveway and I have only a few square feet to clean up around the edges, I have come to terms with snow. I even find it interesting.

    Consider its equivalent in water. I have always known that the previous night's snow was heavier (in moisture) than usual when our neighbor's snowblower chokes on it, but I didn't know how variable that weight is. To find out I checked with meteorologist Tom Niziol of the National Weather Forecast Office at the Buffalo Airport. He tells me that they record not only inches of snow but also the corresponding inches of precipitation, in effect the amount of water produced by melting the snow. And indeed this conversion varies widely.

    At one extreme as little as 5-10 inches of snow converts to an inch of water. This is the heaviest snow due to large-scale or synoptic weather systems. This is not lake effect snow; rather it is Lake Erie flushed onto our doorsteps by larger storms. Just one of them delivers a quarter trillion gallons of water from the lake to Western New York, enough to provide every resident a ton of water each day for a year.

    At the other extreme is lake effect snow. As much as thirty inches of lake effect snow converts to only one inch of water. This is the snow beloved of downhill skiers. Buffalo has a high proportion of lake effect snow, but its 92 inches of snow still contributes a significant portion of our annual 41 inch precipitation average. In contrast, an area near Helena, Montana has almost as much snow -- 82 inches -- with an annual precipitation of less than 13 inches. Clearly, snow shoveling is easier in the Rockies.

    In any case, most of us would agree that we have already had more than enough synoptic and lake effect snow this month.

    Another aspect of snow and one whose exploration provides rich rewards is the individual snow crystal, the source of that sparkling but evanescent beauty that we see when snowflakes drop from a sunlit sky. It simply isn't possible to describe a tiny falling snowflake with the naked eye and once it reaches the ground it either quickly melts or mixes in with its companions. It turns out, however, that naturalists have discovered ways to record and reproduce enlargements of individual snowflakes.

    There are several remarkable collections of snowflake pictures. Easily the finest is Snow Crystals by W. A. Bentley and W. J. Humphries, a 1931 collection of thousands of microphotographs taken in Vermont by Bentley. Copies of this book are in many local libraries. When I checked with the Buffalo Museum of Science about snowflakes, I was surprised when librarian Lisa Seivert immediately identified Bentley. She knew of him, she informed me, because his original glass plates had been donated to the museum and remain one of its most prized collections.

    A close examination of Bentley's beautiful reproductions shows that snow crystals fall into a wide range of forms. While most of the lighter flakes are in hexagonal star or plate shapes -- like the kaleidoscope images of that children's toy -- others are needlelike or rodlike in design. At the heavier extreme particles intergrade into little snowballs called graupel, then sleet and finally hail. Each snowflake is unique; however, the differences are more often in detail than in general appearance.

    Bentley's collection method was complicated and required painstaking efforts, but simpler methods have been developed. One would serve as a project for a young student interested in science. It requires only microscope slides coated with a standard artwork preservative and placed outside to dry. Flakes falling on these slides will leave images of their patterns to be observed or photographed under magnification. -- Gerry Rising


Notes: As originally posted this column contained serious errors, which was especially unfortunate as they seemed to imply -- entirely incorrectly! -- that weatherman Tom Niziol had contributed to them. Tom had provided only the information about snow-water conversion ranges. My errors were discovered and communicated to me by meteorologist Jonathan P. Hitchcock and his corrections have now been incorporated in this posting. I thank Jon for his insights.

A useful reference to lake effect storms and other regional weather is Val Eichenlaub, Weather and Climate of the Great Lakes Region (University of Notre Dame Press, 1979). It was my misquotation of material from this book that constituted the original error in this column.