The big freeze is wrecking crude supply. U.S. output has plunged by 3.5 million barrels a day, traders said. Energy Aspects thinks it will be at least until the weekend before there's any substantial increase, while Citi expects a rebound to take more than a week or two. The bank warned prices will stay volatile in the next few days as refinery closures lead to a build up of inventories. More power cuts and cold weather are in store today. Texas warned outages will last a few more days, backtracking on earlier promises to have power back last night. More than 100 million Americans are under some kind of winter weather advisory as another round of dangerous weather tracks from the Southern Plains to the East Coast, the NOAA said.