Clear ice vs. white ice: What it will take to get the Rideau Canal Skateway open

A person walks along a pathway beside the Rideau Canal, in Ottawa, Wednesday, Jan. 10, 2024. (Adrian Wyld/THE CANADIAN PRESS)

The National Capital Commission has had crews out flooding the Rideau Canal Skateway, with 6.2 km of the canal flooded the past two nights.

But the ice is still too unstable to allow skating, the NCC warned.

This week's cold weather is providing some hope that skaters will be able to hit the ice this year, after last year's disappointing season when the skateway never opened.

In a brief thread on X, the NCC said clear ice is the key to supporting the thousands of people who take to the Skateway every year.

"We need 30cm of GOOD QUALITY ICE before we can open the Skateway to the public," the NCC said (emphasis theirs). "Not all ice is created equal."

The NCC explains that clear ice provides the ideal skating surface. It has fewer air bubbles and is much stronger.

"It is colourless, and forms naturally when temperatures are cold enough for crystals to form below the frozen surface," the NCC said.

White ice, on the other hand, 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."

Snow can be one of the complicating factors that makes the ice on the canal unsafe. Ottawa has seen 41.6 cm of snow so far this month, most of it last week.

However, colder temperatures are moving into the region, which will help freeze the canal. Environment Canada is forecasting low temperatures between -13 C and -20 C over the next five days and highs between -8 C and -13 C. The NCC says it needs 10 to 14 days of consistent temperatures between -10 C and -20 C to make the quality ice it needs to open the canal to skaters.

"The cold weather expected this week will allow our teams to build more ice by flooding!" the NCC says.

"Please keep off the ice. The surface is not stable."

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