Analyzing future of outdoor skating rinks in changing climate as part of NHL Green

As part of the NHL Green initiative celebrating Green Month in April, NHL.com will feature stories on how the NHL is looking to grow and protect the game of hockey and its communities for generations to come. Today, Robert McLeman from Wilfrid Laurier University and the RinkWatch Project, writes about the future of outdoor rinks. NHL Green and RinkWatch have been working together since 2016 with a common of goal of our protecting our game and planet for future generations.

This past winter was challenging for outdoor skating rinks. Cold weather was slow arriving, and temperatures bounced up and down like yo-yo. January saw short periods of intense cold across extending so far south that people in Dallas and Atlanta got in on the ODR action. There were many more mild periods and some rain, but not much snow.

In early February, summer-like temperatures broke records in cities of the NHL's Atlantic and Metropolitan Divisions, and in much of the Central Division as well. Many ODR makers from Chicago eastward decided to break down their boards and get out the golf clubs. Those who hung in were rewarded with a few extra days of skating in mid-to-late March and packed up their rinks about the same time as ODRs on the Canadian Prairies and northern Great Plains, where the ODR season is longer because of the West's generally colder winter climate.

The ideal conditions for ODRs are extended periods with nighttime below freezing and average daily temperatures colder than minus 5 Celsius (23 degrees Fahrenheit) and nighttime temperatures that stay below freezing. We didn't see these conditions very often this winter, even in ordinarily chilly places. As daytime temperatures rise to zero Celsius (32 degrees Fahrenheit) or beyond, it is still possible to have a skateable ODR, but other factors come into play, such as the experience of the rink maker, the construction of the rink and site-specific conditions like the amount of shade.

Having a leak-proof plastic liner inside the ODR is critical when temperatures jump temporarily above freezing, so that meltwater doesn't drain away. This puts large ODRs found in schoolyards, parks and playgrounds at a disadvantage because they are typically built without one. Repeated freezes and thaws can wreak havoc on the ice surface, requiring extra nights of flooding to get it smooth again.

Two things created this winter's unusual weather. First, we are in the late stages of an El Niño cycle, a naturally occurring weather phenomenon that happens once or twice a decade. It's caused by temporary, natural warming of the Pacific Ocean surface, and leads to erratic winter weather in North America, as we've just seen. Second, climate change caused by burning fossil fuels has raised average temperatures, and this exaggerates the warm periods of an El Nino winter. It has also shortened the length and quality of the skating season in eastern North America and threatens to do the same in western North America in the coming decades.

For more than a decade, we at Wilfrid Laurier University have operated RinkWatch, a citizen science project that collects skating condition reports from ODR makers across North America and uses the data to monitor how weather and climate affect outdoor skating. Two winters ago, we gave some of our most dedicated participants, we call them our "Sentinels," automated data loggers. These devices are placed by the rink (in a place safe from errant pucks) where they collect hourly weather readings that are in turn sent to us by smartphone. The graph below is an example of the fine resolution data we can collect for analytical purposes.

Data provided by RinkWatch participants allows us to assess the longer-term implications of climate change for ODRs. In the map below, the dark blue line and shaded area north of it show where average January temperatures were colder than minus 5 Celsius (23 degrees Fahrenheit) in the 1990s. We can think of this as being the ODR "frontier." If you live north of that line, it has historically been cold enough in most winters to build an ODR. Based on current greenhouse gas emission trends, global warming will over the next 50 years push this frontier northwards and into the high mountains of the west, as shown by the red line on the map. In areas between the two frontiers, winters cold enough to build ODRs will become fewer and farther between and will see more winters like the frustrating one we've just come through.

Graph: Solid line represents rink-side temperatures logged in winter 2021-22 at community ODR in Richard's Landing, Ontario (near Sault Ste. Marie). Blue portion of line indicates days when ODR was skateable, red indicates unskateable days. Dashed background line shows average daily temperatures since 1997 for comparative purposes.

Map showing (1) areas where average January temperatures were colder than minus 5 Celsius in the 1990s (blue dashed line and blue shaded areas) and (2) where the same area will be in the 2080s given current greenhouse gas emissions (areas north of the red dashed line). Based upon McLeman et al (2023). Future prospects for backyard skating rinks look bleak in a warming climate. The Canadian Geographer ().

Robert McLeman is a professor, department of geography and environmental studies at Wilfrid Laurier University

To learn more, go to nhl.com/green