(Above: Winter along Poole Creek. Photo by Barry Gray)
There were lots of reports of a series loud bangs on Monday morning in Stittsville and surrounding areas. It’s likely the noise was due to a frost quake, or cryoseism.
They’re usually caused when temperatures rapidly decrease, usually about three or four hours after a significant temperature change like the one Ottawa experienced on Sunday.
Most of the reports from residents mentioned booms anywhere from 3:30am to 8:00am on Monday morning.
A cryoseism may be caused by a sudden cracking action in frozen soil or rock saturated with water or ice. As water drains into ground, it may eventually freeze and expand under colder temperatures, putting stress on its surroundings. This stress builds up until relieved explosively in the form of a cryoseism.
“Additionally, the ground must be saturated with water, which can be caused by snowmelt, rain, sleet or flooding. The site of a cryoseism generally has little or no snow cover to insulate the ground. Geologically, areas of permeable materials like sand or gravel, which are susceptible to frost action, are likelier candidates for cryoseisms. Following large cryoseisms, little to no seismic activity will be detected for several hours, indicating that accumulated stress has been relieved.
A post on the Stittsville Neighbours Facebook group had 100 comments as of about 11:00pm on Monday night. Here’s a sample:
Did you hear the frost quake? Tell us about it in the comments below or email firstname.lastname@example.org