NORTH COUNTY -- Grab something sturdy and hold on tight: Gas prices are about to go through the roof.

What? You thought they already had? Just wait, according to oil industry commentators.

Monday's weekly North County Times survey of retail gasoline prices found evidence of a potent rack inversion, a circumstance that tips the retail market upside down by driving prices at independent dealers, usually the low-price leaders, higher than those at branded retailers and refinery-owned stations.

The average of prices for unleaded regular across North County actually dropped slightly -- 0.8 cents from a week before -- the survey found Monday morning, but the floor seemed to be rising, with only two stations still charging $2 per gallon and some stations charging as much as $2.35.

"The major oil refiners probably have surprised themselves how quickly and easily they got a lock on this market," said Bob van der Valk, bulk fuels manager for Cosby Oil, a Santa Fe Springs wholesaler with customers in the San Diego County market.

"We've seen the unbranded market just go completely inverted," he said.

"The independents will be going up maybe a dime in the next 24 hours, because the rack (wholesale) is up to $1.70 and it's likely to go higher," van der Valk said. "It looks like we're going to set another record."

On the brighter side, diesel fuel seems to be a little cheaper, and by today, van der Valk said, gasoline probably will again be more expensive than diesel.

"In this market, everybody is making money but the poor consumer, who doesn't have many options," said Charles Langley, a consumer advocate at San Diego's Utility Consumers' Action Network. Langley conducts the weekly survey of more than 200 gasoline stations for the North County Times.

Speculation early Monday suggested prices were rising because of a refinery breakdown somewhere in California, causing prices to zoom upward. Late Monday, it was reported by an employee of Valero Energy Corp. who said his company's 140,000 barrel-per-day refinery in Wilmington, a suburb of Los Angeles, had been partially shut down to resolve a problem. There was no word on whether the problem had been solved.

On the New York Mercantile Exchange Monday, unleaded gasoline futures hit an all-time high of $1.263 per gallon. The increase in gasoline futures tracked increases in the price of crude oil, which hit a 13-year NYMEX high on Monday.

The surging oil prices come after terrorist attacks two weekends in a row on oil-production facilities in Basra, Iraq, and in Yanbu, Saudi Arabia.

The price of regular-grade gasoline continued its relentless climb all across the country, and the nationwide average topped $1.84, up about 3 cents from a week earlier.

In North County, the average price of regular gasoline was $2.13, down from $2.14 last week.

Van der Valk predicted the average in North County would top $2.29 by next week and might go higher.

Langley agreed: "We need regulation; until we have it, we're going to see gas priced at $2.50 or even the $3 that some experts are predicting."

Neither saw the possibility of significant relief from the high prices before the end of summer.

The rack price inversion, in which gasoline sold in wholesale transactions is priced higher than the so-called dealer tank wagon price charged by refiners for gasoline delivered to their own branded dealers, led to unusual distortions in the usual price pecking order of dealers in North County.

Usually one of the lowest-priced independent dealers, Mohsen's stations in Oceanside, at Coast Highway and Wisconsin and at Mission Avenue and Airport Road, jumped from $2.06 Sunday to $2.12 Monday.

Costco at Palomar Airport Road and Interstate 5 in Carlsbad is one of the two places that still sold gasoline for $2 Monday. The other was the Arco AM/PM on Tamarack Avenue at Interstate 5.

Contact staff writer Edmond Jacoby at (760) 739-6675 or e-mail to ejacoby@nctimes.com.