UPDATE: It could feel like close to -40 C in Toronto tonight

Environment Canada has issued an extreme cold warning for the Greater Toronto Area and much of southern Ontario as a massive storm, being called a 'bomb cyclone' drops on eastern Canada and US.

A prolonged period of very cold wind chills is expected over the next several days. Temperatures will fall rapidly this evening to reach lows of minus 20 to 25 degrees celsius. Wind chill values due to northwest winds up to 50 kilometres per hour will be in the minus 35 to 40 range tonight.

Temperatures and wind chill values will be slightly lower Friday night, though the extreme cold will continue until Saturday or possibly into Sunday morning.

Extreme cold puts everyone at risk. Cover up: Frostbite can develop within minutes on exposed skin, especially with wind chill. Check on older family members, friends and neighbours. Remember, if it's too cold for you to stay outside, it's too cold for your pet to stay outside.