The harshest chill in decades has triggered loud booms caused by a relatively rare phenomena called “frost quakes”. These occur when water freezes in the soil and expands – the ground suddenly fractures. Also known as cryoseisms, they happen when the ground has been saturated by rain just before a freeze.
Cool, huh?
Nonetheless, it might be bit nerve-wracking to hear those in the middle of the night..!
The bay area enjoys some of the most fabulous weather in the world – sans frost quakes.
One more reason we pay the big bucks to live in the Bay Area!