As Arctic air descends onto portions of the United States, helping break record low temperatures, it is making its presence known by making loud booms. Known casually as “frost quakes” or by scientists as “cryoseisms”,  these loud noises are triggered by extreme stresses in the ground caused by the extreme cold air. When moisture or water freezes deep in the ground, it expands, creating stress on nearby soil and rocks. If the cold air doesn’t allow any melting or that, the stress is eventually released explosively. Heard as loud noises, the surface release of tension can create the ground to shake even far away, resembling a traditional earthquake.

Cryoseisms aren’t very common, but do appear from time to time during periods of extensive, bitter cold. During the winters of 2014 and 2015, frost quakes became a nearly daily experience for residents of central and eastern Canada during bitter cold then.

Residents in and around Chicago, IL have reported many frost quakes there in the last 48 hours. The temperature in Chicago dropped to -23 degrees this morning; the wind even made it feel worse. With extreme cold freezing out the moisture deep into the ground, these frost quakes will be common until warmer temperatures return.