Estimated time to read: 5 minutes

Bruce Devine

Senior Manager, Facilities and Programs

Did you know that the NCC has been maintaining the Rideau Canal Skateway since 1971? It first opened after a team of NCC employees, armed with brooms and shovels, cleared a small section of ice near the National Arts Centre. Over time, the length of the Rideau Canal Skateway grew, as did our knowledge of the science of ice.

NCC staff on the ice, facing the sunlit Skateway.

My team at the NCC cares for the Rideau Canal Skateway. And with the Skateway holding the official Guinness record for the world’s largest naturally frozen ice rink, this is not a small task. Our crews work around the clock to maintain the ice, and provide top-notch facilities and services for the more than one million people who visit the Skateway each year.

So... when does the Rideau Canal Skateway open?

Before we get into the nitty gritty of ice making, let’s address this burning question: when does the Rideau Canal Skateway open?

The skating season typically runs from early January to early March, but it is weather- dependent. The Skateway opens to the public once the surface is at least 30 centimetres thick with good quality ice. For that to happen, our ice experts need 10 to 14 days of consecutive cold weather (-10°C to -20°C).

From water to ice

We start work on the Skateway well before the skating season. In mid-October, Parks Canada drains the Rideau Canal by opening the sluice valves at the Ottawa Locks near Parliament Hill.

We then install:

  • Change rooms
  • Washrooms
  • Sets of stairs
  • Vehicle ramps
  • Universal access ramps
  • Beams at the locks to raise the water to skating level

      When the cold weather first arrives, we allow nature to do its work. As the water in the canal begins to cool, it contracts and the level drops. Once the water reaches a uniform temperature of 2°C from surface to bottom, it begins to crystallize and expand. Because ice crystals are less dense than water, they rise to the surface, where they eventually form a frozen cap.

      Understanding the process of ice formation helps us create and maintain the ideal surface for skating.

      The downtown portion of the Rideau Canal Skateway, with Parliament Hill and the Senate of Canada Building in the background.

      Once a layer of ice has formed, the drilling team uses an ice auger to draw out core samples of the ice. We use the “ice carrot” to measure thickness and check ice quality. When daily testing shows a sufficient thickness (30 cm) of good quality ice for safe public skating, the green flags go up, and entrances to the Skateway open.

      White ice and clear ice

      Not all ice is created equal. Depending on the weather, different kinds of ice form on the Rideau Canal Skateway. There are two main types of ice: clear ice and white ice. 

      An employee measuring an ice carrot, drilled from the frozen canal.

      Clear ice provides the ideal skating surface, because it has fewer air bubbles and is much stronger. It is colourless, and it forms naturally when temperatures are cold enough for crystals to form below the frozen surface. Since the early days, we’ve relied on the ice safety guidelines established by Dr. Nirmal Sinha, who is a scientist with the National Research Council Canada and a world leader in the science of ice. According to Dr. Sinha, a depth of 30 centimetres of clear ice is required before the Skateway can open to the public.

      White ice is cloudy and contains many air bubbles. It forms when fallen snow becomes soaked with water and freezes. There is also a type of white ice that can be made by flooding the surface of existing ice. In 2007, we engaged BMT Fleet Technology to further our knowledge and fine-tune our process. They conducted a study and found that flooded ice, under certain conditions, can be as strong as clear ice. With this flooding process, the thickness of ice needed for skating can be created more quickly at the beginning of the season.

      Partnerships with leading ice experts keep us at the leading edge of ice maintenance. This expertise makes for better ice conditions and greater safety for skaters. I’m proud to say that we now have the in-house expertise to continually improve the ice on the Skateway.

      A weighty issue

      Not only do we monitor the thickness and composition of the ice, we also make sure that there is not too much weight on the ice surface. Keep in mind that the Skateway is a free-floating sheet of ice on a body of water. The weight of crowds, snow and snow removal equipment must be dispersed for the ice to remain safe. The ice inspection team monitors the vertical movement of the ice. If the ice sinks, it means there is too much weight on its surface at that location.

      Maintenance staff pumping water at the surface of the snow-covered Rideau Canal Skateway.

      Snow is the enemy of the ice. When snow accumulates, it forms an insulating blanket over the ice and eats away at the surface. Its weight of the snow also depresses the surface. That is why, after a snowfall, the maintenance crew is quick to get to work on the Skateway with snow blowers and snowplows to clear away the snow.

      Just removing the snow is not enough to turn the Rideau Canal into the world’s largest skating rink. After the snow is cleared away, the ice surface is swept and flooded to smooth out the cracks. This process is repeated each night, weather permitting, to provide a safe skating surface just in time for the early morning skaters.

      Here’s to another great season on the ice!