Prices at local gas pumps have jumped as much as 40 cents a gallon this week as Hurricane Harvey’s 50-plus inches of rain swamped South Texas and closed oil refineries in the Houston area, and shortages are possible. The worst rain event in U.S. history has jolted gas markets just before the busy Labor Day travel weekend, and local and national fuel-industry experts say it’s uncertain how long the disruption to supplies will last, or how high prices will go at the pumps.