The effects of Hurricane Harvey are being felt across the nation, as gas prices are climbing up.

AAA Kansas said Monday that gas prices have “shot up across the country.”

On Monday, the national average for a gallon of unleaded gas was $2.37, which is four cents more expensive than a week ago. It marks the largest one-week national gas price increase of the summer.

In a news release, AAA Kansas said one-fourth of oil refining capacity in the Gulf Coast has been taken offline, according to Oil Price Information Service. That equates to about 2.5 million barrels a day.

Hurricane Harvey also has caused eight refineries in Texas to shut down, while several others are operating at reduced rates.

“No doubt, Harvey has impacted operations and access to refineries in the Gulf Coast,” said AAA spokesman Shawn Steward said in the news release. “However, a clear understanding of overall damage at the refineries is unknown.”

Steward said that despite the country’s overall oil and gasoline inventories being at or above 5-year highs, “gas prices will continue to increase” until there is clear picture of damage and an idea of when refineries can return to full operational status.

On Sunday, Magellan Midstream Partners suspended all inbound and outbound refined products and crude oil transportation services on its pipeline systems in the Houston area, the release said. However, Colonial Pipeline said its Gulf Coast pipeline and terminals are continuing to operate normally.

Harvey is expected to continue to impact the region through the middle of the week with an additional 15 to 25 inches of rain expected over the middle- and upper-Texas coast through Friday.

The Environmental Protection Agency announced over the weekend that it will waive environmental standards on gasoline for select counties in Texas, to help alleviate the the potential for shortages and tight supplies.

The average price of gas in Kansas today is $2.21 per gallon, up three cents from a week ago. At 16 cents less than the national average, Kansas gas prices are 12th lowest in the country, said AAA Kansas’ Steward.

This week’s Kansas cities with the state’s gas price extremes are:

High: Howard (Elk County) – $2.40

Low: Galena (Cherokee County) - $2.03

Despite the increase in average gas price across the state, not all locations saw a rise, AAA Kansas notes. Of the 10 regularly tracked Kansas cities, Emporia and Topeka experienced small price declines and Hays remained the same, while seven cities saw increases. The largest weekly gas price increases were in Kansas City, Kansas, Lawrence and Salina (7 cents), and Wichita (5 cents).