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Cold settled into the Ottawa Valley hard on Tuesday, but with big variations in temperature among cities and towns that aren’t far apart.
At 8 a.m. Environment Canada reported it was -25.4 C in Gatineau, -20.5 C just across the river in Ottawa, and -15.8 C in Kemptville. Renfrew was -25.9 C. Brockville basked at -13.4 C.
The big variations illustrated a feature of the Ottawa Valley that shows up sometimes in cold, still air: The coldest air settles in the bottom of the valley.
Gatineau, where the weather station measures temperatures down near the river, generally shows up as colder in these conditions than Ottawa, which gets measurements on higher ground at the Ottawa International Airport.
Meanwhile there have also been scattered reports of “frostquakes,” which sound scarier than they are. These happened early Monday morning and again early Tuesday.
Frostquakes (the fancy name is cryoseism, which isn’t a typo) occur when ground saturated with water freezes, and the expansion of water as it becomes ice makes stress build up in the ground. When the stress gets too high it releases like a mini-earthquake, but with no destructive power.
It can, however, make a loud bang. A Facebook page run by a group of neighbours in Stittsville collected dozens of reactions from people who heard one or more bangs starting about 3 a.m. on Monday. Some reported seeing the floor vibrate.
One wrote: “This woke me up but not my husband or the kids, a big bang and I swear I felt the house shake! Told my husband when the baby woke him up later (I hadn’t been back to sleep yet) and he went to have a look around. I thought someone drove into the house!”
The real cold arrives Wednesday night.
The Ottawa forecast dips to -30 C. If every city gets the weather that is forecast, Ottawa will be 15 degrees colder than Toronto that night, and five degrees colder than Fort McMurray.
It will also be the coldest night since the winter of 2012-2013. Last winter, although it was long, unrelenting and colder than average, didn’t have a single night that reached -30 C.
tspears@ottawacitizen.com
twitter.com/TomSpears1
查看原文...
At 8 a.m. Environment Canada reported it was -25.4 C in Gatineau, -20.5 C just across the river in Ottawa, and -15.8 C in Kemptville. Renfrew was -25.9 C. Brockville basked at -13.4 C.
The big variations illustrated a feature of the Ottawa Valley that shows up sometimes in cold, still air: The coldest air settles in the bottom of the valley.
Gatineau, where the weather station measures temperatures down near the river, generally shows up as colder in these conditions than Ottawa, which gets measurements on higher ground at the Ottawa International Airport.
Meanwhile there have also been scattered reports of “frostquakes,” which sound scarier than they are. These happened early Monday morning and again early Tuesday.
Frostquakes (the fancy name is cryoseism, which isn’t a typo) occur when ground saturated with water freezes, and the expansion of water as it becomes ice makes stress build up in the ground. When the stress gets too high it releases like a mini-earthquake, but with no destructive power.
It can, however, make a loud bang. A Facebook page run by a group of neighbours in Stittsville collected dozens of reactions from people who heard one or more bangs starting about 3 a.m. on Monday. Some reported seeing the floor vibrate.
One wrote: “This woke me up but not my husband or the kids, a big bang and I swear I felt the house shake! Told my husband when the baby woke him up later (I hadn’t been back to sleep yet) and he went to have a look around. I thought someone drove into the house!”
The real cold arrives Wednesday night.
The Ottawa forecast dips to -30 C. If every city gets the weather that is forecast, Ottawa will be 15 degrees colder than Toronto that night, and five degrees colder than Fort McMurray.
It will also be the coldest night since the winter of 2012-2013. Last winter, although it was long, unrelenting and colder than average, didn’t have a single night that reached -30 C.
tspears@ottawacitizen.com
twitter.com/TomSpears1
查看原文...