Expired News - Polar vortex rattles Canada, US with frost quakes. See why - The Weather Network
Your weather when it really mattersTM

Country

Please choose your default site

Americas

Asia - Pacific

Europe

News
OUT OF THIS WORLD | Science Behind the Weather

Polar vortex rattles Canada, US with frost quakes. See why


Scott Sutherland
Meteorologist/Science Writer

Thursday, January 31, 2019, 6:56 PM - It's happening again! The weather has gotten so cold over central Canada that we're hearing reports of loud booms echoing through the night! What are frost quakes?

As if plummeting temperatures and extreme wind chills weren't bad enough right now, those of us trapped under this frigid lobe of the polar vortex also get the shock and awe of loud booms rolling through our neighborhoods!

On January 30, when temperatures were bottoming out, people took to Twitter to report in on hearing strange booming sounds and feeling the ground shaking.



So, what's going on here?

POLAR STRANGENESS OR HOW I LEARNED TO STOP WORRYING AND LOVE CRYOSEISM

The extreme cold weather that has spread across central Canada this week has been sucking the heat out of everything it comes into contact with.

With this lobe of the polar vortex driving overnight temperatures down to -20Β°C to -30Β°C, and with windchills in the -30s and -40s, it's been causing a rather extreme reaction from nature - rare phenomenon known as cryoseism, or 'frost quakes'.

Cryoseism is a special form of seismic event (ie: earthquake), not caused by moving tectonic plates, but instead, it is a result of the sudden onset of extreme cold.

As the sudden influx of frigid air leaches heat from the ground, freezing temperatures spread deeper and deeper under the surface, where they reach groundwater flowing through soil and percolating through rock, and as a result, that water freezes solid.

Since water expands when it freezes, this newly-formed ice puts sudden and intense pressures on the rock and soil, and when that pressure gets to be too much, the ground suddenly cracks, emitting a loud bang.


The process of cryoseism. Credit: Getty Images/Scott Sutherland

While these can be quite loud for anyone who is in the immediate vicinity, and they can even shake the ground nearby, they are typically not heard or felt beyond about a city block away. This is because they are a very localized effect, that doesn't produce enough energy to be felt or heard at longer distances (as a tectonic earthquake would).

As such, frost quakes aren't necessarily dangerous, although they can be quite alarming.

Most often, frost quakes occur between midnight and dawn, when temperatures are coldest, and in areas with little snow on the ground, since a layer of snow will insulate the ground from the falling temperatures. In some cases, though, strong winds not only produce extreme windchills, but also drive blowing snow, exposing areas of the ground and making them vulnerable to cryoseismic events.

Another possible form of cryoseism that people are hearing right now is when artificial materials - asphalt, concrete, etc - contract in the extreme cold, and fracture under the intense pressure.

This isn't the first time this has happened, of course.

Frost quakes apparently got their first run of media attention on Christmas Day 2013, after an ice storm passed through Ontario and then plunged the province into a deep freeze.

Although frost quakes and cryoseisms have been discussed in scientific literature for years now, going back to at least 1980, it was CBC science reporter Nicole Mortillaro (then with Global News), who was the first to report on these strange Christmas 2013 occurrences.

Since then, they've become a yearly feature on social media, as we repeat this scenario of somewhat mild winter conditions giving way to a sudden deep-freeze.

Have you experienced this before? Did you hear any or feel any frost quakes occurring this week? Let us know in the comments, below!

Sources: Nicole Mortillaro/Global News | CBC News | Maine Department of Agriculture, Conservation and Forestry

WATCH BELOW: YOU'RE PROBABLY CONFUSED BY THE DEFINITION OF "WINDCHILL", HERE'S WHAT IT MEANS



Default saved
Close

Search Location

Close

Sign In

Please sign in to use this feature.