If you woke up because of a couple of loud bangs in the middle of the night, you’re not alone. Some Toronto residents also had their sleep disrupted, courtesy of frigid temperatures causing a “frost quake.”

A frost quake, scientifically known as a cryoseism, is a rare weather phenomenon set off by a sudden drop in temperature, from above freezing to below 0 C, causing water in the ground to freeze.

Soil or rock saturated with water will expand, putting pressure on surrounding soil and rock until an explosion is caused, said Kelly Sonnenburg, a Weather Network meteorologist.

“The rapid cool-down allows groundwater to freeze and then expand causing loud cracking or popping sounds of the ground splitting,” Sonnenburg said. “Even minor shaking or rattling can be occasionally felt.”

The quakes are most common during midnight and dawn, which is when temperatures hit their lowest overnight lows, Sonnenburg said.

Sonnenburg said the sound is similar to cracking thunder.

“My girlfriend and I were sleeping — and my girlfriend is a very heavy sleeper — but this boom woke up the two of us,” said Joel Lopez, who lives near Yonge Street and St. Clair Avenue.

“It was really loud.”

Lopez said the first crack happened at around 2 a.m., and another at 7 a.m. It sounded like a water pipe burst, he said, or someone dropping a dumbbell through his bathroom vent. The second quake, he said, even seemed to cause a vibration.

Environment Canada had issued an extreme cold alert for Toronto for Friday, forecasting wind chill temperatures to reach -30 C in the Toronto area.

Prior to the extreme cold weather Friday, the week’s high temperatures were above 1 C.

Sonnenburg said frost quakes are more likely to occur during winter seasons where temperature is constantly fluctuating, rather than staying at a steady mild, or cool temperature.

Loading... Loading... Loading... Loading... Loading... Loading...

David Venn is a breaking news reporter, working out of the Star's radio room in Toronto. Follow him on Twitter: @davidvenn_

Read more about: