Snowfall is a phenomenon whose characteristics and impact vary considerably across the United States. Snowstorms can disrupt transportation, cause extensive damage and loss of life, and snow removal costs can break city budgets. Lack of snow in normally snowy climes can bring economic hardship to the recreation and water management industries. Snow is also an important player in the climate picture, both reflecting climatic changes and fluctuations as well as exerting an influence on climate. It is clear that a better understanding of the history of snowfall will benefit this nation, for both climatic and economic reasons.
The 20th Century snowfall record for Urbana, Illinois, is examined in this paper as a case study to illustrate both the historical variations of snowfall and the importance of non- climatic influences. Daily snowfall data from the National Climatic Data Center's (NCDC) TD-3200 data base formed the basis for several snowfall parameters, including seasonal total snowfall amount, daily extreme snowfall amount, length of the snow season, and number of days with snowfall. On a broad canvas, the data suggest that the first two decades had more snowfall when compared to the 1920's-40's. Snowfall amount increased in the 1950's-60's, with record amounts falling in the late 1970's. The 1980's-90's have had less snowfall, which is consistent with the 1972-present satellite snow cover record.
Non-climatic influences, such as time of observation, local topography (buildings and vegetation obstructing wind flow), and urbanization (urban heat island), can impact the amount of snowfall measured. A more robust parameter is the number of days with a trace or more of snowfall. This parameter suggests an increasing trend from the early 1900's to the late 1970's, with a marked drop off beginning in the 1980's. A related parameter, the length of the snowfall season, exhibits large interannual variability at the beginning and end of the century when compared to the years in between.
This paper will evaluate the Urbana record in light of other snow studies and with an eye towards station history