The deep freeze gripping Alberta kept relief workers busy Sunday, as they raced to get the homeless to emergency shelters, hand out winter coats and treat hypothermia.

The thermometer read -25 C in Calgary on Sunday, while temperatures dropped to -30 C in Edmonton. Forecasters said the blast of Arctic air, which began a few days earlier, would continue until at least Tuesday.

Cold temperatures are blamed or suspected in the recent deaths of three people in the province.

An autopsy has been ordered in the death of a homeless man whose body was found on a Calgary street on Saturday.

Two days earlier, in Spruce Grove west of Edmonton, two people who were living in a broken-down school bus were found frozen solid. Police suspect they died of carbon monoxide poisoning from running a propane heater inside the vehicle. Autopsies will be done in a few days.

Stampede grandstand becomes temporary shelter

The grandstand building on Calgary's Stampede grounds has been open since Friday night to provide a temporary emergency warming shelter for up to 300 homeless people because all of the regular shelters were full.

Buses have been transporting people from the Mustard Seed Street Ministry shelter to the Stampede grounds.

In Edmonton, the Hope Mission's warming shelter was packed on the weekend with people looking for a place to sleep, safe from freezing temperatures.

Edmonton crews hand out 215 coats

Emergency relief workers have spent the past three nights touring Edmonton's inner city looking for the homeless.

Richard David, a warehouse manager with the city's Emergency Relief Services Society, said workers found one man suffering from severe hypothermia on Saturday night. They brought him into the agency van and called paramedics for help.

Relief workers in the city handed out 215 winter jackets, as well as blankets, to those in need over the weekend and will continue the nightly tours until the cold snap ends.