How is Climate Change Affecting Minnesota Ski Trails?
The Minnesota winter of 2018-2019 could not have been better for cross country skiers--the season was long, and there was plenty of snow accumulation. Can we expect more winters like that in the future? With all the ongoing research on climate change, I wanted to learn more about what global warming means for skiing in the upper midwest.
Weather records show that Minnesota has already warmed approximately 3 degrees over the last 50 years. According to the 2017 report, Adapting to Climate Change in Minnesota, "Annual precipitation increases have been punctuated by more frequent and more intense rainfall events. The heaviest snowstorms have also become larger." Heavy snow sounds great, but what about the warmer temps and potential winter season rain? How will skiing be affected on balance?
Since I'm not a climate scientist, I asked the senior state climatologist for the State of Minnesota, Kenny Blumenthal, for his perspective. He confirmed that the state is experiencing much warmer winters and increased precipitation. He directed me to a resource called the Minnesota Climate Trends tool to find data specific to winter in our state.
I'm a college math instructor, so I enjoyed digging into the data specific to the Minnesota cross country ski season (focusing on December, January, and February). Here’s a graph showing the average annual winter month temperatures and the trend over time.
One obvious takeaway is that Minnesota winters have always been highly variable. For example, the year I was born, 1982, was very cold with an average temp of just 6 degrees (so the stories from my parents about the cold February trip to the hospital for my birth are supported by data), but the next year was fairly warm with an average winter temperature of 18 degrees. As another example, the Birkie was cancelled in 2018 due to the lack of base and a February thaw plus rain making the course impossible to ski, but in 2019 there was almost too much snow after a winter storm dumped a large snowfall onto the already prepared course the night before the race.
While there are many other examples of big temperature swings from one winter to the next, the overall trend is for the temperatures during these winter months to increase by an average of around 0.1 degree per year. Thus, based on the data, I expect this winter to be about a degree warmer than the average winter a decade ago due to climate change, but I would not be surprised if it was 10 degrees warmer or cooler due to natural variability (based on a standard deviation of temperature over the past 50 years of approximately 4.8).
Here’s a graph of winter precipitation over the past 50 years.
Winter precipitation is increasing at 0.09” per decade. If you assume a 1:10 ratio and that the precipitation all falls as snow, an average winter may now produce 5” more snow than 50 years ago. However, with warming temps, at least some of that precipitation will probably fall as rain, and that can devastate a trail in just a few hours.
The verdict
Winters are warming
Winters are highly variable
Winter precipitation is increasing (but that may not mean more snow accumulation on the trails)
It seems fairly certain that there will be many "good" winters ahead for Minnesota skiiers; however, the warming trend suggests that the "bad" ones could be more frequent. I'm glad to see many local trail systems adapting to the warmer conditions by adding snowmaking capabilities. The Birkie, Vasaloppet, and City of Lakes ski races currently have some form of snowmaking with plans for expansion. Hopefully, this artificial snow will even out some of the natural variability and climate-change trends to provide consistently good trails for Minnesota skiers for years to come.
The Minnesota Climate Trends tool can be found here. The program allows you to customize the location, time period, and time of year, so you might want to check it out for your own favorite MN cross country ski region (the above data I presented was for the state of MN as a whole).
