In Canada, people have heard conversations from a distance of several kilometers

From January 17 to February 5, 1947, a strong cold snap was observed in Yukon, in northwestern Canada, and on February 3, the lowest temperature was recorded at -64 °C.

Meteorologist Gordon Toole measured the temperature at the tiny Snaga Airport. The thermometer he used did not drop below -62.2 °C. That meant he had to write it down by marking an extra line on the thermometer. Because of the frost, the pens were useless, so he had to scribble it on the thermometer with a set of dividers.

At such temperatures, people's breath turned into a white powder in the air, while making a ringing sound. As delightful as it may sound, staying outside in such weather for longer than a few minutes could lead to freezing of exposed skin.

One of the more strange effects noticed by the residents of Snaga (Yukon), where the temperature was the lowest, was that the sound changed its properties. When Gordon measured the temperature at the airport, because of the frosty fog, he could not see beyond a few meters. However, he could hear dogs barking in the main village more than 6 kilometers away, and the ice that cracked in the White River about 1.6 kilometers away sounded "loud as gunfire."

What caused these strange sound effects?

At different temperatures, sound propagates differently. For example, if you are close to the ground in the cold, then the sound spreads further. When the air near the ground is cold and the air above it is warm, the sounds are refracted by the warm air to the surface. Then the sound is reflected from the ground and the warm air, spreading much further along the ground than at higher temperatures.

"The temperature inversion caused the sound waves to be deflected back towards the earth rather than rising up," Environment Canada senior climatologist David Phillips told the National Post. "People at the airport could clearly hear the barking of dogs in the city and the conversations of citizens, as if they were nearby, and not 5 kilometers away."

In addition to the disorienting effect of hearing conversations from miles away and the icy fog that surrounded them and impaired their eyesight, people in the city could see clouds of their frozen breath lingering in the air for several minutes.

"It was unusual to see a steam trail several hundred yards long trailing behind a man as he moved outside," Toole said, according to Canada's History website.

"It wasn't easy to get lost. As the observer walked down the runway, each breath remained a tiny motionless mist behind him at head level. These patches of mist from human breathing remained in the still air for three to four minutes before disappearing. One observer even found such a footprint still marking his path when he returned along the same path 15 minutes later."

Of course, if they got lost, they could just whisper and a search and rescue team a few kilometers away would hear them.