Visual metaphor: an object lesson

Visual metaphors often lead chart designers astray; in a bid to create "contextual" charts, they often give up content in search of form, often inadvertently.  In this example (shown right), the NYT wanted to use the ruler metaphor to measure snowfall.

This is a very difficult chart to read as it tries to tell two stories at once: first, the accumulation of snow during the 2006 blizzard; second, the extent of the snowfall relative to 12 historical blizzards.  The "ruler" metaphor requires a tall and thin chart.  Unfortunately, this completely distorts our perception of the passage of the storm.  In the junkart version shown below, we see that the speed of snow maxed out around 15 hours into the storm.

I have placed the historical levels on the side so as not to interfere with the rest of the graph.  I also switched to the relative time axis which tells the story much better.

There is one curious omission on the graph, that is, at what time did the snowfall total top out at 26.9 inches?  This is an inexcusable omission for this chart.

Overall, our chart is much cleaner and easier to understand.

Reference: "Exceeding Forecasts, 26.9 Inches of Snow Hit New York City", New York Times, Feb 13, 2006.