Actually, there is plenty of gasoline available as well. Add to that the refineries won't be idle long, and neither will the rigs in the gulf and there is no problem that should cause more than a burp in gasoline prices - if everything was running intelligently and withour greed involved.
Unfortunately, that isn't the case. Before the was any chance to even guess at how much (if at all) Katrina would affect refining capacity, gasoline jumped 20 cents on the futures market.
Which point out the problem isn't the weather or "shortages" - it's speculators on the futures market driving prices up, greedy oil companies that want to drive their record profits to even higher records and the gas stations basing their price on the futures price and not the delivered price.
So, it all boils down to greed by the oil companies & speculators and FUD by everyone else.
And in case you didn't know, FUD is Fear, Uncertainty and Doubt. (A term coined to describe Microsoft's marketing strategy during the 90's but now fitting oil perfectly.)