Winter weather won’t let up on Chicago, Illinois, as they experienced a series of booms referred to as Frost Quakes.
Frost Quakes (also known as Ice Quakes or Cryoseism) are defined by Wikipedia as a “seismic event that may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice.” As moisture drains down into the ground, eventually freezing may occur causing it to expand under cold temperatures. Once the stress builds up, it is relieved explosively with a loud series of booming noises. There is another type of cryoseism which is a not tectonic seismic and is caused by sudden glacial movements. The saturated ground freezes rapidly when temperatures fall rapidly and the ground shifts, relocating and even splitting open rocks while putting stress on the now hardened soil, which causes loud noises and isolated damage.
There are three conditions that have to be met in order to cause such a disruptive, scary, and potentially damaging event to occur.
- Abundances of rain or heavy snow-melt must impregnate the soil in the ground with water.
- Little-to-no snow on the ground to provide a protective blanket (hence the term “blanketed in snow”) or covering from sudden temperature dips.
- Rapidly decreasing temperatures.
Though the ground in Chicago has been covered in snow, it is possible that the moisture made its way into the soil before the snow had a chance to cover the ground adequately.
It is also worth noting that there is evidence to suggest that, due to climate change, these frost quakes may be becoming more frequent because warmer and wetter air masses are more common over the winter, leaving the ground wet while free of a protective layer.
Because this event is currently considered to be so uncommon (even while writing this, my computer insists I typed something incorrectly), many meteorologists are unclear as to whether or not it’s even occurring in their area. The best thing that we can do is stay educated to the best of our abilities and stay safe in any weather.