RIVERSIDE, Calif. -

The average price of a gallon of self-serve regular gasoline in the Inland Empire recorded its largest daily increase since at least 2010 today, rising 9 cents to $4.298, its highest amount since May 26.

The average price in Riverside and San Bernardino counties has increased 13.4 cents over the past two days and is 18.9 cents more than one week ago, 15.6 cents higher than one month ago and 48.2 cents greater than one year ago, according to figures from the AAA and Oil Price Information Service.

The increases since Monday are the result of a power failure at the ExxonMobil Torrance Refinery which may cause it to flare gases for a week, reducing the supply of gasoline, Marie Montgomery Nordhues of the Automobile Club of Southern California told City News Service.