As heavy snow blanketed much of the GTA Saturday, residents prepared for another deep freeze as temperatures were expected to dip to -15 C overnight.

Flurries fell fast and heavy beginning mid-afternoon Saturday, causing slippery conditions on the roads and sidewalks.

Environment Canada issued a special weather statement that warned of intensified and frequent flurries for parts of southern Ontario, including Sarnia, Toronto and York, Halton, Peel and Durham regions.

The national weather agency said Toronto could expect a total snowfall of five to 10 centimetres by day’s end, as well as 20 km/h winds coming from the north sometime after midnight.

Motorists were warned to prepare for sudden hazardous driving conditions, including zero visibility in bursts of heavy snow and accumulating snowfall on untreated roads.

Fewer than a dozen flights had been cancelled at Toronto Pearson International Airport by early evening Sunday.

Air Canada said flights arriving or departing from Pearson may be delayed or cancelled due to heavy snow. The airline urged passengers to check flight status prior to leaving for the airport.

Meanwhile, Toronto issued an extreme cold weather alert in anticipation of the temperature drop.

The Extreme Cold Weather Alert is called to trigger additional services for the homeless in Toronto.

“Alerts are typically called in the morning for the coming overnight period so that community agencies have sufficient time to call in extra staff to provide enhanced services,” the city said in a statement released Saturday morning.

During an alert, an additional 172 shelters spaces are added to the system and shelter rules are temporarily relaxed.

An extreme cold weather alert is issued when the temperature is predicted to drop to -15 C or lower.

The alert comes just one day after a group of protesters demonstrated at city hall, calling on the city to address Toronto’s high shelter occupancy rate.

The flurries will clear Sunday morning, with an expected high of -7 C to finish off the weekend.