At least three children have died while two others and an adult remain in critical condition following a spate of drowning incidents in Quebec and Ontario this past week, where temperatures reached summer-like heights.

Last Sunday, an unconscious in Drummondville, Que., a city between Montreal and Quebec City, and remains in critical condition. Then, on Friday evening in Newmarket, Ont., a town just north of Toronto, police discovered an unresponsive 20-year-old babysitter in a pool after the . The woman remains in life-threatening condition. And that same night in Chelsea, Que., a municipality near Ottawa, in the bottom of a backyard pool after swimming with friends.

The tragedy continued Saturday morning, when an unresponsive . The child, who was attending a birthday party, remains in critical condition. Later that same evening, by his parents in a Hamilton, Ont. pool.

Also on Saturday evening, police say two children, aged three and five, wandered off from a private residence in Montérégie, Quebec.

The five-year-old was found safe but told a police officer, the three-year-old had fallen into the river. The child was pulled from the water, unresponsive, and has since died.

According to the , a charitable organization dedicated to preventing water-related injuries and deaths, nearly 500 drown annually in Canada.

鈥淒rowning is the number one cause of unintentional death (for children aged one to four),鈥� Sean Duffy, the Lifesaving Society鈥檚 Ottawa-area chair, told CTV Ottawa on Saturday.

鈥淎lways, someone should be watching the water,鈥� Duffy added. 鈥淚f you have a group of people coming over, for example, designate one person who is responsible for watching people in the pool.鈥�

The Lifesaving Society also provides . They include:

  • Making sure that your backyard has a self-closing gate that can be locked.
  • Having secure fencing of a minimum height of 1.5 metres surrounding the pool.
  • Placing a sign near the pool鈥檚 entrance that reads: 鈥淒o not enter without permission.鈥�
  • Making sure that at least one buoyant throwing aid with a rope attached to it as well as a reaching pole are near the pool.
  • Making sure that children are always supervised when swimming.
  • Ensuring, at the very least, that you know basic first aid, such as CPR, if you own a pool.

With files from CTV Ottawa and CTV Montreal.