ClintonWinters

The past winter seemed particularly long and harsh, so I analyzed the severity of recent winters. Scroll down; three different comparisons are here.

1. One obvious comparison was the number of days in which the temperature went below zero. As you can see in the table below, this past winter almost tied the winter of 2002-03 for the most "negative days."

 

2. The second comparison uses a metric for winter severity that was developed by meteorologists (Mayes Boustead, B., S.D. Hilberg, M.D. Shulski, and K.G. Hubbard. 2013. An Accumulated Winter Season Severity Index. Preprints, Amer. Meteor. Soc. 20th Conference on Applied Climatology, Austin, TX.) With this index, points are assigned according to the day's high temperature, low temperature, and snowfall. The colder and snowier the day, the more points that are assigned. The only tweak I made in using the index is that I extended the point counting to March 15 rather than stopping it at Feb 28 (also, the published index includes points based on snow cover, but I omitted that because we don't have such data). We have long winters! The figure below shows that the past winter was one of our most severe in the past 15 years. It followed two milder winters, which is one reason it seemed so severe to us. But the winter of 2002-03 was more severe.

 

3. Finally, one can look at the gradual accumulation of points during the winter (day 1 = Dec 1; day 91 = Mar 1). Steeper parts of the curve show more severe periods, while flatter parts of the curve show milder spells. The figure below suggests that this winter was nearly as severe as the winter of 2002-03 but it started being severe in mid-December rather than at the beginning of December.