Future of Four Seasons in Maine and the Maine Data Literacy Project
Will wetter mean snowier this November?
Background: In 1844 Lydia Maria Child, of Medford Massachusetts, wrote the classic
Thanksgiving poem “Over the river and through the woods”. In the poem she wrote about
“white and drifting snow”. November is typically the wettest month of the year here in
Maine—and it is predicted to get wetter. But, has snow always contributed the same amount
to that wetness? Will we see a lot of our November precipitation this year as snow, or as rain?
The graph below shows Snowfall (in inches) on the left-hand axis and Total precipitation (in
inches) on the right-hand axis. Snowfall is the total of all the snowfalls for the month—
measured as snow on the ground—whether light and fluffy or heavy and dense. Total
precipitation is all of the rain, snow, sleet, and hail for the month—and for this measurement
the snow, sleet, and hail would have been melted, recorded as inches of water, and then
added to the inches of rain for total precipitation. The data are for Novembers in Portland,
Maine from 1871 to 2010.
Data Source: http://www.erh.noaa.gov/er/gyx/climate_f6.shtml
1. Describe what the graph shows about how snowfall and total precipitation has changed in Portland
since 1871. [Purpose here is to elicit description of what the graph shows. Sample response: The graph shows that
there are Novembers with a lot of snow and Novembers with no snow. But there is always precipitation in November.)
2. I interpret the graph to mean… [Purpose here is to elicit an explanation (e.g. of the pattern or variability) or
interpretation of the meaning in terms of the context of the question. Sample response: Through time there are more
Novembers with little to no snow, but at the same time there is the same or more total precipitation. So, snowfall is
contributing less and less to November’s total precipitation. Although an alternative explanation might be that in
some winters there is some snowfall but that it is not light and fluffy snow, but rather heavy snow that packs down.