Drivers in a large part of western Canada are paying more for gas, with prices jumping nearly 20 cents per litre in some major cities in just one week.

In Saskatoon and Regina the average price for a litre of gas on Thursday was listed as 124.9 cents, according to the website Tomorrowsgaspricetoday.com. A week ago, the price of gas, for both cities, was listed at 108.9 cents per litre.

Winnipeggers saw the average price per litre of gas jump from 104.4 cents a week ago to 122.9 cents per litre on Thursday. In Calgary, the average price for a litre of gas on Thursday was listed as 122.9 cents, an increase from 111.9 cents per litre a week ago.

The jump in prices is due in part to a major outage at the BP Whiting oil refinery in Indiana, says the website’s founder Dan McTeague, also a senior analyst with the website Gasbuddy.com.

In a statement released on Wednesday, BP said it shut down the largest of the three crude distillation units at the Whiting plant for "unscheduled repair work."

McTeague told CTVNews.ca that the large U.S. plant supplies about 12 per cent of gasoline to the U.S. Midwest market. As a result, a shutdown there inevitably impacts the market in western Canada.

"What happens in the U.S. Midwest market, affects prices in Canada's prairies and beyond," he said.

Add to that a floundering loonie, and peak demand for gasoline from American drivers during the busy summer travel season, and you have a "perfect storm" leading to higher gas prices, McTeague said.

"It makes a bad situation for Americans a whole lot worse for Canadians," he said.

Those looking for some relief may have to wait for some time, he added, noting that there's no word yet on when the BP Whiting plant will be back in full operation.

"There's no quick fix here, there's no refinery that can be built overnight," he said.

McTeague, who previously served as a Liberal MP for 18 years, said part of the problem is that Canada has not focused enough on the production of gasoline, choosing instead to prioritize oil extraction.

Roger McKnight, chief petroleum analyst at En-Pro International, also blamed the partial shutdown, combined with Canada’s small number of refineries.

McKnight said Canada is “small potatoes” when it comes to refineries, with only 13 in the entire country compared to 143 in the U.S.

Alberta Energy Minister Margaret McCuaig-Boyd said Thursday that the government would look at increasing refining capacity, “but it’s not going to help in the short-term, I’m afraid.”

With a report from CTV Edmonton