- Click to share on Facebook (Opens in a new window)
- Click to share on Twitter (Opens in a new window)
- Click here to share on LinkedIn (Opens in a new window)
- Click to email a friend (Opens in a new window)
(CNN) - Gas prices have skyrocketed in California, rising well above what most Americans are paying at the gas station. In some places, Californians pay $ 5 for a gallon of gasoline.
MIRA: Is California more exposed to risk in the price of oil?
A series of blackouts in refineries reduced the supply of gasoline in the market. The average regular fuel price in California increased to $ 4.18 per gallon, the highest level since May 13, 2014, according to the Petroleum Price Information Service, which collects data for the American Automobile Association, (AAA for its acronym in English).
Gasoline prices in California are the most expensive in the United States: the national average is currently $ 2.65 per gallon.
READ: These are the five countries with the most oil reserves in the world
Most motorists across the country notice that fuel prices decrease or stabilize, which is normal in the fall. Gasoline prices generally fall after the busy summer driving season, AAA said. But that trend has not taken over the west coast this fall.
"We are surprised just because it was unexpected, given that prices have generally declined," said Devin Gladden, a spokeswoman for AAA. "That only speaks of the unprecedented nature of how many refineries fell and how scarce was the offer that ultimately led to the price increase."
Most refineries perform planned maintenance in the fall or winter, which generally does not affect fuel prices because refineries can fix repairs. They can buy gasoline in advance knowing that their facilities will produce less, for example.
LOOK: Oil prices rise after attack on Saudi Arabia facilities
But in the past two weeks, several refineries that supply gasoline to the west coast had unexpected power outages at the same time, which further hindered California's ability to produce fuels.
At most, seven of the 25 refineries in the region were down or with a smaller production capacity, Gladden said.
"Seeing that several refineries have unexpected blackouts at the same time is not normal," said Patrick DeHaan, head of oil analysis at Gas Buddy.
More than in other states, fuel prices in California can sometimes skyrocket, because the state demands cleaner gasoline with less emissions. That makes California gasoline cost more to refine, because it is a special oxygenated mixture that meets the state's strict air quality rules. Refiners have to use a specialized process, and only a few refineries can produce California-approved fuel, making it difficult for the state to import oil.
However, price increases are decreasing as refineries work to resume production capacity. Assuming there are no additional interruptions, DeHaan expects California pump prices to stabilize towards the end of the week.