Illinois does not have any significant mountain ranges or high elevations that can provide snowpack for the state. The highest point in Illinois, Charles Mound, stands at only 1,235 feet above sea level. Consequently, snowpack in Illinois is typically limited and varies greatly from year to year. Snowfall is influenced by winter climate characteristics, including the passage of winter storms and temperature fluctuations.

Runoff rivers and watersheds are important for Illinois' water supply, but they are not primarily fed by snowpack. Instead, the state relies heavily on precipitation and rainfall for water resources. The major rivers in Illinois, such as the Mississippi, Illinois, and Ohio, are primarily fed by rainfall and runoff from surrounding areas.

It is important to note that there is limited information available regarding snow science or historical snow events in Illinois. The state's climate and topography simply do not lend themselves to significant snow accumulation or snow-related phenomena.