By Annika Graf
Despite two ice-related deaths in the Ottawa area earlier this month skaters on the Rideau Canal have few safety concerns about the ice.
“I am sure they check the thickness of the ice. I am more afraid of accidents of skaters on busy days,” says Jacques Gelinas, while skating with his four- and six-year-old daughters, Laurence and Éloise.
“I am putting my trust in the NCC (National Capital Commission),” agrees Sharon Storie, but she will not let her seven-year-old daughter Jessica play alone near the frozen canal.
“No one ever cracked through the ice while the canal was open to the public,” says Marc Corriveau, project manager for the NCC, which operates the canal.
“People are tripping and falling, we have sprained wrists and ankles, but no cases of people falling through the ice,” adds Liette Piché, manager of Lafleur de la Capitale, which provides the canal’s skate patrols.
The NCC maintains an ice safety committee to test the ice over the winter.
Holes are drilled and ice cores are taken everywhere on what is known as the world’s longest skating rink.
“The best quality is clear blue ice,” explains Corriweau. “If we have seven inches (17.5 cm) of clear ice and three inches (7.5 cm) of mushy ice we don’t consider that sufficient to open the canal.”
International guidelines require 25 cm of clear ice for natural ice rinks like the canal to be safe.
Once the canal is open, ice cores are still examined at least once a week depending on temperature changes.
During special events, such as Winterlude, ice safety teams are actually on the ice observing its condition on 25 spots on the canal.
Of most concern is what is called the freeboard phenomenon: As only the very top of an iceberg is actually visible, the major part of the ice layer is under the water surface.
The observers have to be sure that not more than 10 per cent of the layer sinks into the water — the freeboard.
If the water goes up beyond this mark it is not considered to be safe. Additionally, the deflection of the ice crust is monitored during the entire event.
“If we find any reason, the crowd is dispersed and the event is stopped,” explains Marc Graveline, co-ordinator of the NCC’s ice safety committee.
Although the actual skateway is safe, dangers lurk on the edges of the canal where snow banks hide thinner ice.
The snow, which is ploughed and piled on the sides, insulates the ice. The additional weight pushes the ice into the comparably warmer water.
“It is as if you put a blanket on the ice,” explains Nirmal Sinha, an expert from the National Research Council, an NCC ice consultant since the mid-70s.
“On a nice cold day with snow it could happen that in the middle, the ice is growing thicker but on the edges it could melt because it bends into the water,” Sinha says.
“Ice is not guess work. It is a question of knowledge. Little knowledge and overconfidence are dangerous.”
“Kids should stick to the skateway and stay off the snow banks,” advises Corriweau.
The only cases of people falling through the ice have been people ignoring the red flags and trying to skate on the canal while it was officially closed.
This season, about nine cases of people using the closed canal have been reported. Only one broke through the ice.
“No one ever got killed, but they have learned their lessons from this,” says Corriweau. “People have to stay off the ice if the canal is closed.”