Major local roads are reopening across the region, but high winds blowing a fresh layer of snow are still creating dangerous driving conditions.
Stormont, Dundas and Glengarry OPP said at 4:40 p.m. Highway 417 is completely closed in both directions at County Road 34 after a pile-up involving as many as 20 vehicles, including a passenger bus and "several" tractor-trailers.
OPP said two passengers on the bus have been taken to hospital, with many other people involved suffering minor injuries.
The crash site is between Saint-Isidore and Vankleek Hill and police say it could be cleared by 9 or 10 p.m.
Mobile users click here to see a map of the 20-vehicle pileup area.
The northbound lanes of Highway 416 were closed at Roger Stevens Drive, while the eastbound lanes of Highway 417 were also closed at Country Road 29, near Arnprior, the Ontario Provincial Police said.
RCMP also closed the Sir John. A Macdonald Parkway at Island Park Drive due to whiteout conditions.
All of those roadways have been reopened.
From 5 a.m. to 2:45 p.m., Ottawa police responded to about 99 crashes in its jurisdiction.
A wind chill warning was issued by Environment Canada. The overnight low is expected to reach -26 C with a wind chill of -35.
A frostbite warning was also issued by Ottawa Public Health until Tuesday.