Frost quakes: why you may be feeling – and hearing – the earth move

TORONTO – If your new year has started off with more of a bang than you expected, chances are Mother Nature is to blame.

Large swaths of southern Ontario have been experiencing a phenomenon known as frost quakes, a comparatively rare meteorological event that only takes place in unusual circumstances.

Meteorologists say recent ice storms, thaws and deep freezes have created ideal conditions for the frost quakes that have caused public consternation and even alarm.

Dayna Vettese, a meteorologist with the Weather Network, said the reaction is perfectly justified.

Frost quakes _ scientifically known as cryoseisms _ are more commonly found in glaciers than in residential areas, she said.

The quakes take place when water is allowed to seep into cracks in the soil, then quickly turns to ice as a result of a rapid drop in temperature.

Vettese said water accumulation usually takes place as a result of a heavy rain storm, adding the sequence was slightly different this time around.

“We had the ice storm or freezing rain event, then we had warm temperatures, or just about freezing at the surface. Then the temperatures plummeted after that,” Vettese said in an interview from Oakville, Ont. “That’s why we’ve seen a couple of these events between the ice storm and the beginning of 2014.”

Vettese said the thaw that took place shortly after Christmas allowed the ice that accumulated during the storm that blanketed much of the country to seep into the soil. The subsequent deep freeze caused that water to turn to ice, which then expanded and pried chunks of the ground apart.

“It’s almost like an earthquake because it’s very close to the surface. You will feel a little bit of shaking, maybe if you’re sitting in a chair and it happened, or you’re lying in bed, or some of your dishes might rattle.”

For many, the frost quakes were heard rather than felt. Twitter was abuzz with reports of people being wrenched from sleep as a result of loud cracks or bangs outside their homes.

“The loud boom at dawn was not a very clumsy burglar, but rather a #frostquake,” wrote one Twitter user.

“That frost quake was not a fun experience. Keep thinking my house is being attacked by demons like in paranormal activity,” tweeted another.

Social media was also flooded with bewildered queries from those wondering why a country renowned for its cold temperatures does not experience frost quakes more often.

Northern Canada, for instance, routinely experiences temperatures well below the -24 Celsius documented in Toronto on Friday morning.

Vettese explained regions that experience consistently cold temperatures are safe from the disruptive booms, adding such areas don’t experience the thaws required to lay the groundwork for ice buildup.

“You need these temperature swings in order to get that water into the ground and get that melting going on,” she said.

Such temperature swings are expected to continue dominating weather patterns over the next few days.

Weekend forecasts for southern Ontario call for everything from highs above 0 to lows below -10. For good measure, Environment Canada has issued a special weather statement predicting heavy snow over the region on Sunday night.