As Florida drivers hit the road to escape Hurricane Irma, the demand for gasoline has outpaced supply, leaving filling stations throughout the state short of fuel.

"It's horrible, man," said Aaron Izquierdo, who waited in a long line of cars at a Shell station in Doral on Friday. "Just yesterday I was in line for two hours to wait for gas, and by the time we got to the pump there was no gas."

In Gainesville, 60 percent of the gasoline stations were without fuel, according to Patrick DeHaan, senior petroleum analyst at the crowdsourcing website Gasbuddy.com. In Miami, it was 40 percent.

Even in the Tampa area, far from the expected landfall, more than a third of stations lacked fuel, he said.

Irma is coming fast on the heels of Hurricane Harvey, which clobbered the Texas and Louisiana coasts and left a quarter of the nation's oil refining capacity off-line.

But the problem in Florida isn't supply. It's demand.

Gasoline companies usually know pretty much where a hurricane is going to hit and can target supplies to that area. Irma has been harder to forecast, so a lot more people have chosen to evacuate.

"Unfortunately, because everyone panicked because of the uncertainty...we ended up with shortages in multiples areas of the state," said James Miller, spokesman for the Florida Retail Association.

"The amount of motorists filling their tanks is overwhelming the system. Trucks can't get to the stations fast enough," DeHaan said. "And at the rack, or what some might call fuel terminals, tanker trucks can't be loaded as fast as motorists are filling their tanks."

State officials are trying to keep supplies flowing, by waiving restrictions on the number of hours that truckers transporting gasoline can work and even providing tanker trucks with police escorts. The White House too is trying to make it easier to bring fuel into the country by waiving the Jones Act, which bars foreign-flagged vessels from transporting goods between U.S. ports.

Still, finding fuel can be dicey.

Scott Alderman, who lives in Broward County, was out for a bike ride this morning when he passed a gas station without fuel.

"But a tanker truck was pulling in and, like the pied piper, there were 15 or 20 cars following him," he said.

Alderman has lived through hurricanes before and knows that, once the electricity goes out, it can be days before gas is available again. So he immediately went into action, racing home to tell his wife to fill up her car.

She got to the station within five minutes, he said. But she still had to wait nearly an hour to fill up her tank.

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