Some roads in southwestern Ontario have been closed due to blowing snow causing whiteout conditions.

In Bruce County, Highway 21 was closed late Friday morning between Kincardine and Port Elgin, while Highway 9 was closed around the same time between Kincardine and Walkerton.

Periods of poor to zero visibility were reported along those highways, and Bruce County OPP are asking all drivers to stay off the roads unless travel is essential.

Highway 6 was closed shortly after noon between Tobermory and Wiarton, and around 1:30 p.m. between Fergus and Arthur.

Highway 86 was closed Friday evening between Wingham and Amberley.

In Perth County, no roads were reported closed as of 7 p.m. Friday, but pockets of low visibility are expected as the day continues and winds pick up.

Waterloo Regional Police responded to more than 20 crashes Friday afternoon, in both rural and urban areas.

As of 7 p.m. Friday, a blowing snow warning remains in effect for Huron-Perth, Grey-Bruce and the northern part of Wellington County, including Mount Forest and Arthur.

Environment Canada forecasts winds of 40 to 60 km/h, gusting to 80 km/h, through the evening.

Combined with falling snow, visibility could fall to less than 500 metres at times.

Conditions are expected to improve overnight as winds diminish.

In Waterloo Region and the Guelph area, forecasts call for temperatures to rise overnight, hitting a high of -7 C Saturday morning, although wind chill values will hover around -29.

Snow and blowing snow are expected until mid-Saturday afternoon as winds stay high.

The City of Kitchener has declared a snow event, meaning cars are forbidden from parking on city streets between 11:59 p.m. Friday and 11:59 p.m. Saturday.