A 70-vehicle pileup closed a busy Canadian highway on Friday. The multi-car collision occurred due to slick conditions and poor visibility.

One of Canada's busiest highways, the 401, has reopened after it was closed in both directions due to the 70-vehicle pileup east of Toronto. Several cars lost control as snow started to fall, reducing visibility and making the road slippery. The collision occured near Newcastle at around 3p.m, the Canadian Press reports.

More than a half mile stretch of the highway was filled with mangled metal and vehicles, causing more than six miles of the highway to be shut down.  Five people were taken to the hospital, two of which were in serious condition. Another was flown to another hospital, but their injuries were not life-threatening.

The east-bound lanes of the highway were closed until 10:30p.m. and the west-bound lanes were closed until midnight. Dozens of people were left standed in the cold and they waited for help to arrive. Eventually buses were sent to the area to take the people to a recreation center to be interviewed by police. They were then returned to their vehicles.

An investigation will take several days since there were so many vehicles involved. The crash was likely due to the weather, so it serves as a reminder to drivers that they need to slow down and take caution while driving in such conditions.

The crash caused voting at the Ontario Liberal leadership convention to be extended for several hours as they waited for the highway to clear.