Refinery fires spike gasoline prices.

RVers in West Coast states are about to see a big spike in gas prices, the fallout from a fire that cut production at one of the region’s largest oil refineries.

USA Today reported that gasoline prices, now averaging $3.87 a gallon in California, $3.72 in Washington and $3.69 in Oregon, are expected to spike to $4.15 to $4.25 a gallon over the next week to 10 days following Monday’s partial shutdown of a Chevron refinery in Richmond, Calif.

Nationally, gasoline prices have climbed 27 cents a gallon in the past month. While the refinery fire will drive prices along the West Coast, it will also lift the national average above year-ago levels.

“August looks like a very touch-and-go month for the entire country,” says Oil Price Information Service (OPIS) analyst Tom Kloza, who expects price relief after Labor Day. For the year to date, gasoline has averaged $3.61 a gallon — 10 cents more than the average for all 2011, the most expensive year ever, he says.

Patrick DeHaan, senior oil analyst for gasbuddy.com, expects California, Oregon and western Washington state to experience price spikes like the ones that hit major parts of the Midwest in June, when an Illinois refinery shut down and three others in the state cut production.

“The West Coast is on the launch pad waiting for takeoff,” DeHaan says. “We’re talking over $4 a gallon, easily. It’s not going to be good for motorists.”

Meanwhile, prices in Illinois, Indiana, Michigan, Wisconsin and Minnesota remain as much as 39 cents a gallon higher than the national average of $3.65 a gallon, according to the OPIS. “The infection is going to spread from the Midwest to the West Coast,” DeHaan says.