Temperatures across the Prairies continued to soar Tuesday, rising 10 to 15 degrees above seasonal averages as a heat wave moved through Alberta, Saskatchewan, Manitoba and into northwestern Ontario.

The heat wave swept into the Prairies over the weekend, breaking heat records in several cities dating back as far as the 1930s.

A heat wave is defined as three or more consecutive days of temperatures 32 C or higher. Extreme heat can lead to heat cramps, heat exhaustion and heat stroke, Health Canada's website states. To avoid heat-related illnesses, Health Canada suggests staying in the shade, limiting activity to morning and evening, and drinking lots of water.

In Alberta, temperatures peaked over the weekend, with a high of 30 C in Calgary on Sunday, and started to drop on Tuesday.

Saskatchewan was hit hardest on Tuesday, with the southern city of Coronach being the hot spot for the country, hitting 40.1 C by mid-afternoon.

Regina has hit some of the highest temperatures in Saskatchewan, reaching 30 C and above every day since July 18. The average temperature for Regina in July is 26 C.

The extreme heat and humidity led to surgeries being postponed on Monday and Tuesday at the city's Pasqua Hospital after the facility's air conditioner broke down. Health officials said the humidity could result in an increased risk of infection.

Farmers across the province said the hot weather was causing drought and heat damage in their fields, especially in the southwest. If the heat keeps up, the crops could ripen too quickly, meaning lower yields and less money for Saskatchewan farmers.

In Winnipeg, the heat was so intense that not only temperature records melted — so did vinyl records. And there were reports that plastic storefront signs also melted. The temperature reached 34 C on Tuesday. 

Across Manitoba, the high was 34.9 C in the northern city of Gillam.

Manitobans have tried to beat the heat by snapping up air conditioning units. Clayton Rifkind, of Oreck Canada in Winnipeg, said the store had to get an emergency shipment of the units on Saturday just to keep them in stock.

The heat wave moved into northwestern Ontario on Tuesday, with the highest temperature reaching 34.2 C in Fort Severn.

Relief is on the way for the Prairie provinces, as forecasters say a powerful cold front is set to move in. Temperatures already began dropping in Alberta on Tuesday, and starting Wednesday a cooling of 10 to 15 degrees will start sweeping across Saskatchewan, reaching Ontario by Thursday.

This cooling off should help bring temperatures in the region down to the seasonal average or slightly below.