The winter storm that hit Chicago last week and into the weekend has sent Chicago straight into hibernation mode. Snow covers all corners of Chicago, mist is rising from the lake like some apocalyptic omen, the river is beginning to freeze, and the air has reached that teeth-chattering chill that threatens frostbite.
It’s safe to say the Midwestern winter has arrived and, as temperatures continue to plummet, Chicago collectively musters up the strength to see out another stretch of this severe season hoping to fast forward to spring.
Over the last couple of days, there have been noises and trembles coming from icy areas that meteorologists call “Frost Quakes”. It turns out the recent weather has created the perfect conditions for these frost quakes but they’re something very few of us are familiar with so we’ve here provided a breakdown of what they are to counter any confusion.
What is a Frost Quake?
Formally known as a cryoseism, frost quakes aka ice quakes, are weather-related seismic events caused by sudden cracking in frozen earth or rock that has been saturated with water that has become ice.
Though they are a seismic naturally occurring phenomena and can sound and feel like earthquakes they are in no way near as severe.
When do Frost Quakes occur?
When water drains into the ground it can freeze and then expand when temperatures rapidly drop below freezing.
This water trapped underground causes sudden expansion forcing itself upon its surroundings and cracks the surrounding ground causing mini-explosive sounds.
A sufficient amount of water must be located at a sufficient depth below the ground for a frost quake to take place. They also require a high amount of precipitation in a relatively short time that is then frozen shortly after due to subzero temperatures.
Frost quakes also cannot occur when there is a significant amount of snow. As little as six inches of snow acts as an insulator for the ground and stops freezing air rapidly affecting water trapped below the surface.
Consequently, conditions need to be just right for frost quakes to occur. They require significant rainfall, little snow, and a sufficient amount of water to be affected deep enough underground with rapidly changing temperatures.
Are Frost Quakes dangerous?
How loud the noise a frost quake makes depends on the amount of water that is quickly frozen beneath the surface. The loud sounds created can wake people from their sleep or cause shock but they are not dangerous in the same way earthquakes can be.
Though the vibrations caused by frost quakes can be measured and recorded on a seismometer they are very rarely felt above ground as they have nothing to do with the shifting of tectonic plates or rising magma which happens with more serious seismic events.
They crack the ground beneath the surface and occasionally may cause fissures to roads and sidewalks but they are never severe or sudden enough to cause harm or endanger people’s safety.
What to do if a Frost Quake happens?
Frost quakes are instantaneous and are incredibly hard to predict. If you experience a frost quake it will be without warning but it will be harmless and no danger will follow.
In fact, many people consider experiencing a frost quake a stroke of luck due to their rarity.
More information on frost quakes can be found at www.accuweather.com.
[Featured image from Shutterstock]