A powerful winter storm bearing down on southern Manitoba is reducing visibility and closing highways on Boxing Day.

Environment Canada estimates between 18 and 33 centimetres of snow has fallen in Winnipeg. The federal weather agency said most of the storm's precipitation has fallen, but high winds are continuing to pick up snow and reduce visibility.

The Colorado low behind the storm was just south of Lake of the Woods early Monday morning and tracking northeast, Environment Canada said. The system has left piles of snow, making it difficult to drive or even walk on sidewalks.

The following are some of the major highways in Manitoba that were closed:

The Trans-Canada Highway between the Saskatchewan border and Winnipeg and from Winnipeg to the Ontario border.

Highway 75, between Winnipeg and the U.S. border.

Highway 59, to the U.S. border.

Highway 200, from St. Adolphe to Winnipeg.

Highway 23, from Highway 21 to Highway 18.

Highway 10, from Highway 2 to Highway 3.

Some volunteer to clear snow

Environment Canada warned drivers to postpone any non-essential travel until conditions improve.

Larry Halayko, executive director for construction maintenance at Manitoba Infrastructure, also urged motorists not to venture onto highways if they have the option of remaining at home.

"Plows are out there and crews are doing their best to clean things up as quick as they can, but it was a significant snowfall," he said in a telephone interview.

Provincial crews were focusing their efforts on major arteries such as the Perimeter Highway, the Trans-Canada Highway and Highway 75, Halayko said.

And while snow plows were out clearing streets on Monday, some were volunteering to clear snow for others including David Taillefer.

"It's winter we have to cope with it," Taillefer said.

Others could be spotted walking downtown with shovels doing what they could to help.

Winnipeg airport returns to normal

After more than 30 flights were cancelled on Sunday, normal operations largely resumed Monday morning at Winnipeg James Armstrong Richardson International Airport, although some delays and cancellations persisted.

Tyler MacAfee of the Winnipeg Airports Authority said travellers should check the WAA website or the airline to see if flights are on time.

"A lot of the flights that were coming in last night [Sunday], those planes were going to turn around and go back out this morning — with a plane not coming in, it's obviously not here to go out, so those flights have been cancelled or delayed until they can get another plane," said MacAfee.

MacAfee recommends all air passengers check the status of their flights and give themselves plenty of time to arrive at the airport.

"The roads are going to be tricky, traffic is going to be moving a little bit slower, so give yourself lots of time to the airport," he said.

Walking in a winter wonderland. <a href="https://twitter.com/hashtag/cbcmb?src=hash">#cbcmb</a> <a href="https://t.co/LI36rV6vhZ">pic.twitter.com/LI36rV6vhZ</a> —@bkives

Monday storm forecast

CBC Manitoba meteorologist John Sauder warned that the blizzard would make highway travel difficult through Monday.

"It's not about the additional snow that's going to fall," Sauder said.

"It's about the wind and how the wind stays strong through the rest of today. We've seen winds gusting to 60 kilometres per hour overnight. Today, through the rest of Monday, northwest winds will be gusting from 30 to 50 km/h."

Visibility for the southern part of the province was estimated to be at 400 metres or less for at least four hours because of heavy snowfall.

Sauder warned drivers to expect near-zero visibility on highways.

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