On this graph, the x-axis (horizontal) displays time, in years (snowfall seasons)
The y-axis (vertical) displays snowfall, in inches.
There is a lot of seasonal variability, based on hte zig-zag shape of the graphed line.
Remember, the range is the difference between the smallest snowfall amount (blue circle) and the highest snowfall amount on the graph (red circle).

The x-axis here again displays time in years (snowfall seasons).
There are two y-axes here. The far left y-axis shows snowfall in inches, whereas the far right y-axis shows the seasonal snowfall departure from average (anomalies) in inches.
Blue areas indicate higher than normal snowfall, whereas red areas indicate lower than normal snowfall.
Note that the lowest seasonal snowfall for Wisconsin (circled in pink) is about 22 inches (left y-axis), which makes it about 26 inches below average (right y-axis).

The x-axis on this graph is displaying years, whereas the y-axis is displaying snow cover (in 10^6 square kilometers).
Note, this graph conveys snow cover, not snow depth, or total snowfall.
While there is considerable year-to-year variability in snow cover between 1920 and 1970, the average snow cover during that time period is relatively consistent (37.5x10^6 square kilometers).
Between 1990 and 2005, there is again some level of variability, but it's important to note that the average snow cover during that time is lower than in previous years. Note the red and blue boxes above.

The x-axis again shows years (snowfall seasons), whereas the y-axis displays the number of days of 1-inch or more of snowfall during that season.
Note, this graph does not convey seasonal snow depth or snowfall, but rather just the number of days with 1-inch or more of snowfall each season.
Note the maximum (red circle) and minimum (blue circle) years.
While there is an upward trend ini the last decade, it's too soon to tell if that's will be a long-term trend.