The 401 -- one of Canada`s busiest highways -- has reopened after being closed in both directions for several hours after a massive pileup east of Toronto.
Ontario Provincial Police say snow was falling, the road was slick and visibility reduced when about 70 vehicles collided yesterday 80 kilometres east of Toronto near Newcastle.
It happened around 3 p.m. Friday afternoon, and left a one-kilometre stretch of highway littered with mangled metal.
"Basically, people who weren't comfortable with the conditions were [driving] too slow in their lanes and people ... who were more confident weren't adjusting their speed," one witness recalled.
"I've seen a lot of accidents over the years but I've never seen a chain-reaction crash like that."
The wreck sent five people to hospital, two in serious condition.
Of the five who were hospitalized, one was later flown to Toronto's Sunnybrook Hospital, but OPP spokeswoman Cst. Linda Wolf said none of the injuries was life-threatening.
The chain reaction wreck closed a 10 kilometre stretch of the highway's east-bound lanes until nearly 10:30 p.m., and the west-bound lanes until shortly before midnight.
Dozens of people were left stranded in the cold for hours.
Wolf says buses were enlisted to take people from the crash site to a recreation centre in Newcastle where they were interviewed by police before being returned to their vehicles.
Due to the number of vehicles involved, Wolf says the investigation into the crash is likely to take several days.
And while weather conditions are certainly being looked at as a possible factor, Wolf says the crash clearly demonstrates the need for motorists to slow down and take extra care in dodgy driving conditions.
Lake effect snow widespread
The white-out conditions were the result of lake effect snow that moved through southern Ontario Friday, which combined with an Alberta clipper to bring snowfall to much of the region.
By the time the evening commute rolled in, snow squalls and whiteout conditions were being widely reported.
"Lake effect snow is created as the cold air moves over warmer waters resulting in rising motion, which produces clouds and localized heavy snowfall," explains Dayna Vettese, a meteorologist at The Weather Network.
"We have one of the coldest air masses we have seen in a couple of years and after a long, hot summer and fall, the lakes are warm, creating the perfect conditions for lake effect snow."
Saturday's forecast will include less snow across the region, aside from some gradually diminishing flurries in some locations, and accumulations of up to 5 cm around the Bruce Peninsula.
For those who have been struggling to stay warm, the cold snap across the region will soon come to an end.
This week has been a frigid one with temperatures taking a dangerous plunge.
Windchill values dipped into the -20s, prompting an extreme cold weather alert for places like Toronto.
Starting on Sunday, however, temperatures will begin to climb, with daytime highs in the mid-to-high single digits by Tuesday and Wednesday of next week.
With files from the Canadian Press