Some drivers heading east on Highway 16 near Radisson, Sask. are facing a 150 kilometre detour to get to Saskatoon.
Water was rushing over the road east of that community in both directions Thursday. It had been that way since Tuesday night.
Lighter vehicles were diverted north all the way to Blaine Lake, while heavier vehicles were still being let through.
"Basically, it's the overfill that's flowing from Radisson Lake," Corey Loessin, who farms near the Yellowhead Highway in the Radisson area, told CBC News.
"It typically comes through there in some quantity, but nothing like we're seeing this year. It's just a huge flow compared to most years."
The water was more shallow on the westbound side of the Yellowhead Highway, and traffic was still being let through.
There were a number of other secondary highways around the province that were flooded out.
Drivers were advised to check Highways Hotline before heading out.