The legendary American Birkebeiner, also known as the Birkie, is North America’s largest cross-country ski race. The 50 kilometer ski race is located in Sawyer County of northern Wisconsin and takes place annually in mid-February. The trail transects the hilly, wooded forests between Telemark Resort near Cable, WI and the town of Hayward, WI. Approximately 8000 skiers, 2,000 volunteers, and over 15,000 spectators participated in the Birkie events of 2010. The influx of visitors has a roughly $4 million economic impact for Sawyer County over the span of the weekend. The Birkie trail also attracts many recreational cross-country skiers throughout the winter, and many own vacation property in the area. In addition to the economic impact of the Birkie, there is a healthy cross-country ski culture in the Sawyer County area supported by the local community. This cultural connection can be witnessed during the race finish on Main Street, the Barnebirkie ski race for 1,300 three to thirteen year olds, and by the fact that the number of Birkie volunteers is roughly equal to the population of its host city, Hayward (2,342).
Since the first race in 1973, the Birkie has been shortened six times and cancelled once due to weather related conditions; with four of these adaptations and one cancellation happening since 1990. The weather plays a major role in determining the success of the event. According to the American Birkebeiner Ski Foundation, which organizes the race and maintains the 85 kilometers of trail year round, reasons for shortening or canceling the event include large bare patches that can’t be patched, poor lake-ice conditions and poor logging-road conditions for emergency vehicle access. Since weather is the primary factor determining the success of the event, examining past climate data and future climate predictions can provide us with some understanding of how climate change is impacting this event.
According to researchers at the University of Wisconsin-Madison between 1950 and 2006 the Sawyer County area winter average temperature has warmed around 3 to 4.5 °F. They also found: a 4.5 °F increase in winter average daily low temperatures, a 4-10% reduction in the number of days with a high temperature below 20 °F, and a 15 to 18% reduction in the number of days with nighttime low’s below 0 °F. Interestingly, spring is coming earlier by 3 to 9 days. In general, Sawyer County has seen warmer winters, with higher high and even higher low temperatures.
Researchers have also downscaled global climate models using local historical climate data to generate fine-scale climate change predictions state wide. For Sawyer County they project that from 1980 to 2055 there will be: 21 fewer nights below 0 °F, fewer average annual freezing days, 16 to 18 fewer days with high temperatures below 20 °F, and 7.5 to 10 days earlier onset of spring. Moreover, the average annual winter temperature is projected to increase 9 °F, and the daily high and daily low are also expected to increase 6.3 and 9.0 °F, respectively. Additionally, for Ashland, WI, northeast of Hayward, researchers projected a decrease in the probability of frozen precipitation (e.g. snow, sleet), especially early and late in the winter. Since Ashland is slightly buffered from climate change by Lake Superior we can expect an even greater reduction in the probability of frozen precipitation for the Hayward area, which is further inland. Furthermore, a group of researchers from the Universities of Wisconsin and Iowa project that by the mid 21st century there will be a 25 to 40 cm reduction in snowfall and a 5 to 20 cm reduction in mean snow depth (on March 15th) for Sawyer County. In summary, by 2055, warmer winters, with warmer nights, a lower probability of snow fall, shallower snow pack, less snow cover, and an earlier onset of spring are expected. Considering the fact that the Birkie trail covers over 50 km of ground we can expect to see more adaptations to the event as warmer winter temperatures and less snow create unsafe race conditions.