"Travel is slow," said RCMP constable Christina Wilkins.
"Motorists who don't absolutely have to drive today are recommended not to do so and wait for the conditions to become more favourable."
Secondary Highway 881 was also shut down for most of Friday, completely cutting off traffic in and out of Fort McMurray.
Highway 881 was closed after two transport trucks collided 35 kilometres north of Janvier, at kilometre marker 240. No one was injured in the crash.
The route was reopened after 2 p.m. MT, although police advised against travel, saying it was still dangerous. A tow ban has been put in place, meaning tow trucks will be unable to help drivers who get stuck on the highway.
Snow and freezing rain prompted the province to close a long section of Highway 63 on Thursday evening.
Alberta Transportation decided to keep the road closed Friday morning after consulting with RCMP.
"Icy conditions due to freezing rain, coupled with fog and wind and variances in temperatures as well as falling snow, have made that highway completely unsafe for travel," said Alberta Transportation spokesman Parker Hogan.
Route vital link to Fort McMurray
Dozens of semi trucks sat parked Friday on the side of the normally busy highway, waiting for police to open the route.
“The conditions keep changing. And here we sit,” said Stan McKee, a fuel hauler who first arrived at the blockade at 7 a.m. Friday, waiting for the chance to continue to Fort McMurray.
With so much truck traffic using the road, McKee said the closure is expensive for many Alberta companies. Still, he supports keeping the road closed until conditions improve.
“The fact that it is such heavy volume on this road makes it very dangerous," he said.
"Everyone just needs to be patient right now."