Hundreds of oil rigs in the Gulf of Mexico shut down and were evacuated as a precaution.

Those rigs are responsible for about 17 percent of US oil production.

But pump prices could surge sharply if the storm triggers flooding, or power outages that shut down Gulf Coast oil refineries much longer.

With uncertainty ahead, people are already having a tough time adjusting to the latest increase.

Katie Foppe, who was traveling from Highland, Ill., to Omaha, Neb., with her five kids, said, "I'm definitely worried about gas prices going up. It used to not be a big deal about traveling and now we have to really think about if we can afford it."

Betty Stowe and her husband are going to visit their kids in Vancouver, about 3,000 miles from their home in North Carolina.

They have to go there because their kids couldn't afford to visit.

Stowe said, "They don't have as much disposable income as we do so it doesn't affect them."

And if Isaac does more damage than expected, Jason Owens said they'll still pay the price no matter how high it goes, “What are you going to do really? You're not going to pay it? It's going to take 40 million people to not drive to send a message."

But Mike Wright with AAA in St. Louis is hopeful prices will drop after Labor Day. He said, “Hopefully they will plateau when we get through the aftermath of the storm, the refineries get back up and running and pipelines get there taps turned back on we should see moderation in gasoline prices.