A rather large boom heard around the GTA on Christmas Eve wasn’t Santa’s sleigh hitting rooftops but a frost quake.
CityNews meteorologist Natasha Ramsahai said tweets began coming in about loud noises around the dinner hour and peaked around midnight.
“You hear booms. You hear loud cracks. You hear what you think is a meteor – almost like a sonic boom kind of sound,” she explained.
— SpeedRacer1999 (@Speedracer1999) December 25, 2013
A cryoseism, also known as a frost quake, does happen frequently after ice storms but are quite uncommon in the GTA.
“Obviously it’s been over 40 years since the GTA has had an ice storm so we haven’t had reports of a cryoseism in the city for at least that long,” said Ramsahai.
A frost quake is caused when rain and ice seep down into the soil and then freezes when temperatures drop.
“Water expands when it freezes and when it expands in frozen soil it literally puts a lot of stress on that dirt and will release that energy all of a sudden, very much like an earthquake releases that energy and shifts the ground,” said Ramsahai.
Temperatures dropped to the -17 to -20 degree range Tuesday evening which lead to the frost quakes causing cracks and craters in the snow and ice on some people’s property.