NEW YORK (Fortune) -- While Congress and Bush administration officials have been working to complete a bailout plan and stem the financial contagion on Wall Street, a different kind of economic crisis emerged across the South this week: A severe, hurricane-related gasoline shortage has curtailed trucking from Atlanta to Asheville, N.C., and created a wave of panic buying among motorists.

The return of gas lines has largely flown under the radar of politicians who are usually keenly attuned, because their constituents are, to what's going on at the pump. But more of the Capitol gang should be paying attention to this.

That's because nationwide our gasoline inventory is shockingly low. Liquidity must be restored soon to this market, or we could be facing a crippling run on the gasoline bank. And if you think Americans are outraged about Wall Street, wait until their Main Street grocery store doesn't get the bread and milk delivery for a week or two.

Back to the '70s

The scenes over the past several days in places like Nashville, Tenn., Anniston, Ala., and western North Carolina looked like file footage from 1979 - with bags over empty gas pumps and quarter-mile long lines of cars waiting to fill up at stations that hadn't run out. AAA reported that drivers were so desperate that they were following tankers to gas stations to ensure a fill-up.

In Georgia, Gov. Sonny Perdue got a waiver from the Environmental Protection Agency to temporarily allow stations to sell high-sulfur gasoline. (Correction: An earlier version of this story said Louisiana received the waiver and incorrectly named Perdue as that state's governor.) In Alabama, Gov. Bob Riley ordered a state of emergency to prevent price gouging by station owners that do have gas.

What's going on? The immediate answer is that the double whammy of Hurricanes Gustav and Ike, which swept through the Gulf of Mexico earlier this month, caused much of the Gulf's oil drilling and refinery production to be shut down. In particular Ike, which hit refinery-rich Southeastern Texas on Sept. 13, caused massive power outages in the Galveston and Houston areas.

As of this week, more than a dozen refineries around Texas City and Port Arthur were not operating at full capacity and, according to the Department of Energy, six refineries, with a combined capacity of 1.6 million barrels a day, were still not running at all.

A bigger problem

But while the current shortages can be traced directly to the two hurricanes, the severity of the problem points out a bigger issue: The U.S. has been operating for a while with razor-thin spare gasoline capacity.

In its most recent Weekly Oil Data Review, Barclays Capital pointed out that the U.S. gasoline inventory has reached its lowest level since August 1967, when demand was a little more than half its current level of 9.3 million barrels a day. At 178.7 million barrels, inventories are 21.6 million barrels below their five-year average.

None of this surprises industry watchers such as Matt Simmons, the chairman of Houston energy industry investment bank Simmons & Co. and chief spokesman for the Peak Oil movement. I recently wrote a profile of Simmons for Fortune ("The prophet of $500 oil") and I can report that he has been warning about the potential of gasoline shortages in the U.S. for months.

"Our system is so fragile," he told me recently. "All you need is a tiny change to go from 'Oh, we're in fine shape' to an unmitigated disaster."

Simmons points out that the gasoline weekly stock reports have been trending sharply downward since last winter (with a brief upturn in the spring), and that even before Gustav and Ike we were in "just in time" supply mode.

Getting back to a safer level of extra capacity isn't simple, either. Once the refineries get back up and running, they'll drain the already low crude oil inventories. Unless gasoline demand stays low, Simmons believes, we'll have a hard time clawing back to stability.

That's why he worries about a top-up catastrophe that could cripple the trucking industry and disrupt food deliveries.

As he told me the other day: "If we end up having gasoline shortages, the odds are about 90% that Americans will do what we always do: We'll top up our tanks. And in topping up our tanks, within three or four days we'll drain the pool dry and then within seven days we'll run out of food."

That sounds awfully dire. And it probably won't happen. But, then again, a couple of months ago hardly anybody would have predicted that AIG would collapse, Congress would be mulling a Wall Street bailout, and '70s-era gas lines would be back.