A snowstorm heading into Manitoba this weekend could be one of the biggest on record.

A snowfall warning has been issued for all areas across the southern part of the province, and it has already started in Brandon, where light flurries are now falling.

CBC Meteorologist John Sauder expects the flakes to start showing up in Winnipeg at about 9 p.m.

"It looks like through the late evening here in the Winnipeg area and then this whole thing gets really ramped up overnight and by tomorrow it's just a snow day," he said.

The snow will be heaviest in the southwest before spreading eastward through Saturday.

It will taper off Saturday night, though some light snow may linger over the eastern half of the province on Sunday.

Once it's done, there could be as much as 40 centimetres of snow in some pockets of the province, especially near the Turtle Mountains and east of Riding mountain National Park.

Winnipeg might see as much as 30 cm.

Initially, the storm forecast released on Thursday suggested the city would be at the edge of the system and see only 10 cm.

City officials say crews are ready and will be working around the clock to clear the streets during and after the weekend storm.

There are 300 pieces of snow-clearing equipment ready for plowing duty.

Although winds won't be particularly strong, the combination of heavy snowfall and winds in the 30 km/h range will likely produce near-zero visibility at times, according to Environment Canada.

Drivers should be prepared for very poor conditions across much of southern Manitoba on Saturday

Freezing rain

Already, freezing rain prompted the closure of the Trans-Canada Highway between Portage la Prairie and Brandon for three hours early Friday.

It reopened just after 5 a.m.

Meanwhile, the Perimeter Highway is ice-covered as are parts of Highways 75, 8, 9, and 59.

Crews are out sanding and salting but drivers are urged to take caution.

Top 10 daily snowfalls in Winnipeg

• 38.1 cm — March 4, 1935 (53.1 cm from March 3-6 in total)
• 35.6 cm — March 4, 1966
• 33.0 cm —April 12, 1872
• 31.8 cm — Jan. 2, 1907
• 31.0 cm — Nov. 10, 1919
• 30.5 cm — Dec. 26, 1916
• 30.5 cm — March 6, 1916
• 30.5 cm — March 9, 1925
• 29.5 cm — March 25, 1904
• 29.0 cm — May 11, 2004

Some other recent large snowfall events in Winnipeg:

• Dec 30-31, 2006 — 32.0 cm at the airport and 29.0 cm in Charleswood over two days.
• April 4-7, 1997 — 48 cm of snow and ice pellets over four days
• Nov 7-9, 1986 — 35.8 cm over three days

The greatest one-day snowfall from any station in Manitoba was 76.2 cm on Nov. 18, 1906 at Dauphin, followed closely by 76.0 cm on April 19, 1992 at Virden.