A quick freeze is expected with the passage of a cold front today. From a late-morning high temperature in the lower 50s, all the way down to 11 degrees tonight, these are perfect conditions for "frost quakes."
The technical term is cryoseism. That's when liquid water that flows down into the ground around rock and limestone cracks with abrupt freezing temperatures. This occurs because water expands when it freezes (the same reason soda cans explode when they freeze and why a milk jug of water will expand to a ball-shape if it freezes).
The water in all of these cracks can expand so quickly, they create mini explosions…explosions of water and ice. These booms can sound deep but really aren’t enough to physically shake the ground. Where they occur, they can easily to startle livestock, pets, and unsuspecting people. They can be heard for up to a mile.
-Meteorologist Eric Sorensen