ROCKFORD, Ill (WIFR) -- Many residents across the Stateline wrote to the 23 Storm Team about how they were awakened by loud sounds last night. The same story is expected to happen tonight in spots with the sub-zero temperatures continuing. The loud sounds were actually caused by a natural phenomenon known as "cryoseism," also known as an "ice quake" or "frost quake."
This event occurs when water seeps into the ground and freezes. Combined with these frigid temperatures, that water then expands and adds stress on its surroundings. Most of the time, it can put stress on rock or soil. In many cases across the region, the water puts so much pressure on its surroundings that the soil or rock then cracks suddenly. That is the "boom" or "crack" residents may have heard outside of their homes, the "quake" component of the ice quake.
Jonathan Lageman, Supervisory Hydrologist at the U.S.G.S. in DeKalb says that this phenomena is not unheard of, but there are many things that need to happen in order for them to occur. He says, "You will see them happen over bodies of water, where you will see infiltration of water into soils and rocks and sometimes concrete. This can happen anywhere where material can be saturated that has to release that freezing pressures."
In addition to hearing these noises from nearby bodies of water, local residents could hear water within pipes or roofs expanding quickly with similar noses occurring on area walls and roods. There are also good chances that other parts of your home comprised of wood and plastic will also "pop" or "crack" because both of those materials tend to contract at times in frigid temperatures.