Here are the cold, hard facts about the dangerously low temperatures in much of the U.S. this week.

In Australia, temperatures reached 116 degrees Fahrenheit last week in Adelaide. The country has experienced drought for so long that some children have hardly experienced rain.

While not all of these extreme events can be attributed to climate change, the profound changes in the earth’s atmosphere raise “the likelihood of a large number of extreme events,” one scientist said.

The details: Our maps show the polar vortex.

Voices: “I’m cold and I’m afraid.” The lowest temperatures are expected tonight, and homeless people are particularly at risk.