Frigid cold set in Tuesday in the wake of an Alberta Clipper that dumped nearly 20 centimetres (eight inches) of snow on Sarnia-Lambton Monday.
Lambton's Medical Officer of Health has issued the third cold weather alert of the season, and Environment Canada has an extreme cold warning in effect.
Meteorologist Peter Kimbell said the forecast low Tuesday is -21 C (-6 F) with a dangerous overnight wind chill of -34 C (-29 F).
"We have the cold basically in place now, and it's going to continue to get colder," said Kimbell. "Temperatures falling to -21 C tonight, probably coming very close to breaking a record for the 29th, and then the 30th and possibly the 31st as well. With very, very cold temperatures. The record's been hovering around the -20 C, -21 C threshold."
Conditions should improve Friday as milder air moves into the region.
Lambton Public Health said we should limit our time outdoors, and take precautions when we are outside by dressing in layers, and shielding exposed areas from the wind.
Sarnia police said there were no major incidents in the city but OPP reported multiple collisions across Lambton County in Monday's storm.
The eastbound lanes of Highway 402 were closed Tuesday morning from Hickory Drive to Glendon Drive at Strathroy while vehicles were removed, and the passing lane westbound near Sexton Road was closed for removal of a tractor trailer from the median.
Road conditions had improved Tuesday. The MTO said at noon that major highways including the 402 were generally partly snow covered to bare and wet with fair to good visibility.
Over 20 snowplows and maintenance vehicles were clearing snow in Sarnia.
Superintendent of Roads Tony D'Agostini said Tuesday they were working on side streets but it would take awhile. He asked residents to be patient and not park vehicles on the street.
School buses were cancelled across Sarnia-Lambton Tuesday morning and high school exams have been pushed back one day.
To view the list of cancellations, click here.
