 Anticipation of a threat to supply by a potential Hurricane Chris coupled with high demand during an ongoing heat wave were cited as factors in the price move.In New Orleans, officials including Mayor Ray Nagin prepared for a possible evacuation of the city if Chris entered the Gulf of Mexico as a hurricane.The evacuation plan included moving all residents out of the city as a worst-case scenario, intended to avoid a re-occurrence of Hurricane Katrina around one year prior.