The Foothills was blanketed in darkness last night just before 9 p.m.

And it wasn't just because the sun had set, it was because of a power outage across southern Alberta.

It affected customers in High River, Blackie, Cayley and surrounding areas.

It also briefly affected Diamond Valley, Priddis, Millarville, Longview and Eden Valley.

Amanda Sadleir, corporate communications manager with AltaLink says their crews had power restored within minutes to the majority of customers.

"Around 8:53 last night we experienced an outage at our High River substation.  Our control center noticed that there was an outage and we determined there was a piece of equipment that failed at the substation." 

At this time AltaLink isn't sure what caused the piece of equipment to fail as they continue to investigate.

Sadleir says it affected quite a few customers, but power was restored relatively quickly.

"We were able to get power back online within about seven minutes to the majority of the customers that lost power. And the remaining customers were restored within 30 minutes.

It affected upwards of 13,000 customers.