Crude prices are having one of their best days in a year, rallying as much as 5% amid concerns that icy weather in the oil patch will crimp domestic supply, while tighter sanctions on Russia and Iran may eliminate barrels from global markets.

The U.S. Treasury Department is sanctioning Russian oil companies, tankers, officials and executives. Oil prices jumped on worries that crude supplies would face disruptions. Oil prices jumped more than 3% on Friday as the U.

Oil prices rose Friday morning, touching prices last seen in the fall, as traders digested the possibility of further U.S. sanctions on Russia.