Tim LeRiche, a spokesman Epcor Power, which provides electricity for Edmonton, says the agency that oversees electricity distribution in the province has issued a directive for utilities to reduce consumption.
LeRiche says the blackouts in Edmonton have already started. He says each blackout will last about an hour, and he has no idea how long they'll continue.
Calgary and Lethbridge have also instituted rolling blackouts.
No one with the Alberta Electric System Operator could be reached for comment.
A news release issued by the agency on Monday afternoon urged Albertans to conserve power, and said that there is difficulty dealing with enough power to supply the grid.
"Higher than average temperatures have pushed the demand for electricity in Alberta to record highs and some generation is unable to supply energy to the grid," the news release states.
"The hot and humid weather has increased demand for electricity primarily due to the higher use of air conditioning and irrigation systems."
The release does not mention blackouts. It says people should continue to reduce power consumption until 6 p.m. Monday.
LeRiche noted that drivers needed to be careful as traffic lights were out in some parts of Edmonton.
"If there are lights in the house that shouldn't be on, turn them off. If there are jobs that require electricity that can be done later, delay it. Every little bit helps," LeRiche said.
Both Edmonton and Calgary recorded temperatures in the low 30s on Monday afternoon.
The City of Lethbridge issued a news release Monday stating that it, too, had been informed by the AESO that it must reduce consumption in order to avoid overloading the provincial grid.
It said it began rotating outages at 3 p.m. and would continue to work with the province to restore power as quickly as possible.
A spokesperson for Enmax, which supplies electricity in Calgary, said the utility would try to avoid implementing blackouts in areas with hospitals, as well as the Calgary Stampede.
Officials in Medicine Hat, meanwhile, said Monday that the city was isolated from the grid, meaning the situation was stable. City spokesman Wilbur McLean said the city was even managing to export electricity to other centres.
(The Canadian Press, CHQR, CJCY)