Operators stopped pumps along the 800-mile pipeline at 8 p.m. Monday. The line was reopened at 2 a.m.
A spokeswoman for the Alyeska Pipeline Service Co. said two tankers are berthed in Valdez now. Pipeline officials hope weather will improve enough to start transferring oil to the tankers around 9 a.m.
Tankers can't be loaded when bad weather makes deploying a boom around docked tankers too dangerous, or when waves slosh over the boom, rendering it ineffective for containing a spill.
The enormous oil storage tanks at the tanker port had been filling because ships haven't been able to load since Sunday morning, said Michelle Egan, spokeswoman for Alyeska.
At the time of the shutdown Monday night, the tanks were filled to 91 percent of capacity, she said.
Oil companies on the North Slope began to throttle back on oil production Sunday, but pipeline operators finally decided the six-hour shutdown was necessary due to the storage crunch and the inability to load ships, Egan said.
This isn't the first time the pipeline has been idled due to weather menacing the tanker dock. High wind and waves forced a shutdown in November 2006.
The pipeline has been moving about 750,000 barrels of North Slope crude oil per day through December.
The operator, Alyeska, is an Anchorage-based consortium of companies that own shares in the pipeline, which was started up in 1977. The owners are BP, Conoco Phillips, Exxon Mobil, Chevron and Koch Industries.
BP, Conoco and Exxon each operate a fleet of huge, double-hulled tankers that haul oil from Valdez to West Coast refineries.
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