There's cold, and then there's cold.

A large part of the US experienced what truly cold temperatures were when a polar vortex came down from the arctic, bringing with it freezing cold temperatures that destroyed property, stopped activity and even killed.

We love to complain during winter, but the reality is that the colder weather is often dangerous. While we are told to bundle up, there's a point on the thermometer where normal winter wear doesn't cut it.

Sunday morning was at one of those points.

A bus driver was on his regular route when he came to a stop. There was a man inside the bus shelter, but he didn't seem to have noticed the bus.

Douglas Cowan was on the bus and described the heroic actions of the driver.

The driver called to get the man's attention, but he remained slumped over. The driver lept off the bus and carried the man inside.

"There was no response, so the driver quickly got him on the bus," Cowan told CTV Edmonton.

The temperature in Edmonton that day was -22°F with a wind chill of -40°. That's enough to cause frostbite in under five minutes - and enough to kill.

"I think I heard him say that he'd been there most of the night. It's just a miracle that he's alive," Cowan said.

"I feel that this bus driver saved a life. He's truly a hero."

The driver spoke to the man on the bus after calling paramedics and calmed him down while they waited for help. The man was taken to hospital for treatment and remained in stable condition there.

In the US, over 20 people's deaths have been directly related to the cold weather. A study in 2015 found that cold weather actually kills 20 times more people than hot weather.

Bus drivers are particularly important when it comes to combating the deadly cold. Not only do passengers routinely wait in the cold but homeless people try to find warmth in bus shelters.

"This is just a perfect example of a bus driver being alert and jumping into action," Transit spokesperson Rowan Anderson said.

The cold weather for Edmonton is expected to continue and areas around North America will now brace for power winter storms.

Be careful out there everyone!