It's being called one of the worst storms to hit midwestern Ontario in nearly 30 years, and it stranded as many as 400 vehicles on roads or in ditches in Huron, Perth, Grey and Bruce Counties.

Most roads are closed in the four counties, although the County of Perth says Perth Road 135, Perth Line 26 and Perth Road 131 have reopened.

All roads were closed as of Monday evening, marking the first time in over 40 years all roads in the counties have been closed.

Residents are encouraged to call 511 or visit for up-to-date road conditions on provincial highways. In Grey and Bruce Counties, information on local roads can be obtained by calling 1-866-266-7569.

Officials expect to make a decision on reopening the roads early Wednesday morning.

Plows were back on the roadways Tuesday trying to clear the snow. The situation is most severe in Bruce and Grey where plows had to be pulled from the roads due to zero visibility.

Two plow drivers in Huron County even spent Monday night sleeping in their vehicles after getting stuck in the snow, while several operators from the four counties had to spend the night at the work yards because they couldn’t make it home.

A number of emergency crews also didn’t make it home Monday night and had to stay on the job.

Snow clearing crews are dealing with drifts between eight and 10 feet high on some roads. In Huron County, 18 plows, three graders and two big snow blowers are trying cut through the drifts.

Brent Glasier, Bruce County’s Highways Operations Supervisor, says it’s the worst storm he’s seen since 1977.

Hundreds of people are also without power in midwestern Ontario and hydro crews won't be able to help until the weather subsides.

Bruce Power brought in extra staff Monday night in preparation for the storm and if the roads remain closed, some workers will have to stay at the nuclear plant.

Police urging people to stay off roads

Across the region, people are being advised to avoid any non-essential driving.

On Monday night, plows were needed to lead police to a pregnant woman and an ill man who were each stuck in their car for more than eight hours.

Meanwhile on Tuesday afternoon, Owen Sound police closed a section of 8th Street East, from 9th Avenue to 28th Avenue East due to whiteout conditions.

Grey Bruce Health Services was asking anyone with non-urgent appointments at the organization's six hospitals to stay home.

All elective surgery has been cancelled until further notice and while the chemotherapy and dialysis clinics in Owen Sound remained open, patients are being contacted to discuss their appointments.

The Huron County Health Unit has also cancelled services for Tuesday.

However warming centres are available at the Brussels and Seaforth Community Centres and South Huron Recreation Centre in Exeter during the day.