Did you hear those loud sounds last night? With new snow on the ground and clear skies temperatures in Rockford, temperatures all around the stateline plunged below zero early this morning and if you're like me you awoke to unusually loud creaking and popping sounds in your home. Don't call 911, you are not alone. Many area residents reported what sounded like gunshots coming from their decks outside as wind chill temperatures dropped to minus-30 degrees in some locations.

Is it someone trying to break in, the famous Rockford Bear making a return appearance? Nope, it's a "frost quake." This is a winter phenomenon where your home or apartment will which generate  loud sounds that will occur when the temperature plunges in the winter.

According to Norbert Delatte, civil and environmental engineering department chairman and professor at Cleveland State University in a interview with Cleveland.com,

Pretty much all building materials – wood, concrete, steel – expand with heat and contract with cold, the foundation of a house stays at a more normal temperature where the outside of the house is trying to shrink against it, so whatever connections there are between the foundation and home, they would be making some noise.Sound travels further through the cold, dense air and the lack of activity overnight make the noises sound louder then they would during the day

The concrete foundation "footers" on houses are constantly shifting depending on the temperature and moisture in the ground.

In extreme cases, the ground freezes, cracks and shakes slightly — what's known as a cryoseism, or "frost quake." Nails can contract and slip in wooden homes, creating a "pinging" sound.

As Rockford enters the deep freeze this week, we may experience more of these frost quakes. The good news is that in most cases, these noises indicate minor movements that do not typically cause damage, but popping noises can also be the cause of a bursting pipe.