The city's chief medical officer issued an extreme cold warnings as temperatures are expected to drop significantly on Tuesday night.
According to Environment Canada Environment, temperatures should drop to -17 C with windy late evening in the early morning.
Temperatures should rise to -4C by Wednesday afternoon.
The alarm will be in effect "until further notice", the city said.
Usually, the city issues an extreme weather warning, when Canada's Environment and Climate Change predicts temperatures of -15 C or colder, or winds of -20 C or colder.
"Exposure to cold weather can be detrimental to your health. Hypothermia occurs when the body temperature drops below 35 degrees Celsius and can have serious consequences, including organ weakness and death. Frostbite can also occur in cold weather when the skin freezes and, in severe cases, can lead to amputation when deeper tissues are frozen, ”the city warned in a statement.
The city is opening a warming center at Metro Hall as part of the alert, as well as expanding the streets and making transit token shelters available. The center will be open until the alarm sounds.
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