While people are looking for ways to stay cool as the temperature remains high, authorities are warning that a day of fun in the water can turn tragic quickly.

In just a 24-hour period this weekend three children have died while swimming, with the most recent being a 12-year-old boy from North York.

He was swimming with friends at Sherkston Shores, along Lake Erie, when he disappeared under the water.

Emergency crews were able to locate his body but were unable to save the boy.

Meanwhile, on Friday, a ten-year-old girl and her seven-year-old brother drowned in a swimming incident, also along the shores of Lake Erie.

Lisa Harder and her brother David were pronounced dead at Victoria hospital in London, OPP confirm.

A third sibling is expected to survive after he was rescued by another family member.

Eight children from the Harder family were swimming that day. The oldest was 19 and the youngest was David. The 19-year-old managed to save the third family member, a nine-year-old, but lost sight of the other two under the water, police said.

They were reportedly swimming with others in shallow water when they became distressed for unknown reasons.

Barbara Byers, from the life-saving society, says even if kids are not swimming it’s a good idea to keep a life vest on them if they’ll be anywhere near water.

“As much as life jackets are really important in a boat, they’re also an excellent life-saving device for children when they’re near the water,” Byers said. “The life jacket will ensure they are right-side up and their head and mouth are out of the water.”

On average there are 500 drowning deaths in Canada every year, with more than 100 of those taking place here in Ontario.

“And when they are in the water, you need to be right with them, you need to keep them in arm’s reach and your eyes on them at all times,” Byers said.

Drowning is the second-leading cause of preventable death for children under 10-years-old.