A Loud Crack on a Cold Winter Night? It Might Have Been a Frost Quake

Frost quakes can cause a sound like a sonic boom

Downed trees
Downed trees litter the street during a recent ice storm in Toronto. Courtesy of Flikr user PJMixer

In case you missed the memo, it's really, really cold outside in large parts of the country. When it gets this cold (colder than Mars!), the Earth itself can start to do some really strange things. Up in Canada, some residents of Toronto were woken up by what sounded like sonic booms coming from the beneath the ground.

The noises, says the CBC, were caused by “frost quakes.” 680 News:

A frost quake is caused when rain and ice seep down into the soil and then freezes when temperatures drop.

“Water expands when it freezes and when it expands in frozen soil it literally puts a lot of stress on that dirt and will release that energy all of a sudden, very much like an earthquake releases that energy and shifts the ground,” said Ramsahai.

Frost quakes aren't related to earthquakes, despite their similar names. But, frost quakes can be picked up by seismic wave monitors.

The seismic signal of a frost quake, as recorded by a seismometer in Ontario. Photo: Natural Resources Canada

Frost quakes, also known as cryoseism, can start to happen when the temperature gets down to around -4 F, says Natural Resource Canada. So, as cold temperatures continue to grip the land over the next few days to weeks, keep your ears tuned to the sounds of the Earth.

More from Smithsonian.com:

This Cold Snap Is Making It Colder Than the Surface of Mars

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