'Ice can be very deceiving,' warns expert after recent tragedies

There are renewed warnings about the dangers of venturing onto thin ice or near bodies of water after several incidents where people have drowned in lakes and rivers across Canada over the past week.

In Ottawa, four teenagers who had reportedly gone skating fell through the ice on the Rideau River in the city's south end on Wednesday night.

Two teens aged 15 and 17 were able to rescue themselves and were taken to hospital to be treated for mild hypothermia, while divers recovered the bodies of 17-year-old Ahmed Ahmed and another 16-year-old boy.

The tragedy follows the deaths of a family in Alberta who had been reported missing Christmas Day after going off-roading in Lac Ste. Anne County and the death of a man who fell through the ice on Calgary's Bow River, also on Christmas.

The search continues for the body of a four-year-old girl who fell into the Mistassibi River in Quebec while sledding with her mother last Friday.

"Ice can be very deceiving, the looks can be deceiving. So, people are looking at the ice thinking that it's solid when it's not," said Stephanie Bakalar, corporate communications manager with the Lifesaving Society in Ontario.

She said about a third of all drownings in Canada happen between October and May because of thin ice and frigid water.

Bakalar said temperature fluctuations, like what Ottawa has experienced over the past month, can be especially dangerous.

"Maybe to your eye it looks like it's frozen, but underneath, it's likely not. As temperatures go up and down, it'll sort of freeze a little, melt a little, refreeze a little, and this results in what we call 'dirty ice' and this is very unsafe," Bakalar said.

She said people should measure the ice's thickness using an auger, a device that allows you to drill down and take a sample core of the ice.

She said the ice needs to be at least 10 centimetres thick to carry the weight of a single person, and thicker if there are more people.

If you take a car onto the ice, she recommends the ice be at least 20 to 30 centimetres thick.

The area where the Ottawa teens fell through the ice is near locks on the Rideau River and often serves as a popular skating spot for locals, according to the local councillor.

"Typically, it's used by many residents. We can't always say it's safe, because we don't know," said David Brown, councillor for Rideau-Jock.