As a member of the MIT Ski Team, I frequently look at the upcoming forecasts, hoping for more snow. Unfortunately, the unseasonably warm weather lately has made training very difficult. This is a chart of yearly snowfall at the team’s home mountain, Ragged Mountain, from opensnow.com. It shows for each season from 2010-11 until now, what percentage of average snowfall the mountain has had. 
The chart uses circles of different heights to correspond to that’s years percentage, and it also includes different colors of the circles to go along with that. Seasons of low snowfall have orange circles, while seasons with more snowfall have bluer circles.
The audience of this chart is people like me, who ski at Ragged often. Since I’ve been skiing at Ragged for a few years now, I know how much snow they had last year and the year before. So when I look at the chart and see that this year has a much lower mark than the previous couple of years, I have a good sense of how much snow to expect. I believe that that’s the goal of the presentation. It shows skiers the trend in snowfall, in a way that’s easy to compare from year to year.
I think that this presentation is effective because I can easily see that this season I should expect less snow than in recent years, which lines up with what the weather has been like lately. However, one detail I wish this chart included is the actual number of inches, rather than only a percentage. Even just an indication of how many inches “Average” is would be a helpful specification.