From Yahoo: Crude oil is getting cheaper — so why isn't gas?: "
"Right now, in an unusual market trend, West Texas crude is selling for much less than inferior grades of crude from other places around the world. A severe economic downturn has left U.S. storage facilities brimming with it, sending prices for the premium crude to five-year lows.
But it is the overseas crude that goes into most of the gas made in the United States. So prices at the pump will probably keep going up no matter what happens to the benchmark price of crude oil."
Suppose you were hedging gas prices using West Texas Crude futures. The fact that the two prices do not move in unison is what we call basis risk.