The slick of oil in the Gulf -- a blob now three times the size of Rhode Island -- is moving toward the west and could threaten the Louisiana coast Monday afternoon, according to the lastest forecast.
Emergency managers continued hurried preparations ahead of the possible landfall.
Shifting weekend winds could push patches of oil along the shoreline west of Louisiana's Barataria Bay to Isles Dernieres on Monday.
"Sandbags are getting filled, and we'll be airlifting them,'' said Brennan Matherne, a spokesman for Lafourche Parish, about 60 miles southwest of New Orleans.
About 400 sandbags were being filled and ready to be taken by helicopter to help block off five sections of marshland that touch the Gulf and were identified by local officials as the most vulnerable to oil. If the oil comes ashore, officials think it'll be easier to clean from the parish's sandy beach than from the marshes.
"We haven't dealt with an oil spill, but we've dealt with enough hurricanes to be calm,'' Matherne said.
Preparations onshore continue as BP works to try and stem the leaking well spewing oil a mile below the surface. Experts appear to have no certain plan for sealing anytime soon the runaway well 5,000 feet below the gulf's surface.
"There's a lot of techniques available to us. The challenge with all of them is, as you said, they haven't been done in 5,000 feet of water,'' BP Chief Operating Officer Doug Suttles told NBC's Today show Monday morning.
With what had been thought to be the best immediate solution to contain the leak, a 78-ton steel and concrete box known as a cofferdam, resting useless on the sea floor, the Gulf's fragile ecosystem seemed to face a worst-case scenario -- a leak that will go on perhaps for three more months until a relief well can be drilled to intercept, then seal, the leaking one.
On Sunday, a top Coast Guard official suggested that experts might try to cork one of the two existing leaks by stuffing shredded tires, golf balls and other debris into the well's failed blowout preventer. But it was uncertain how seriously that option was being considered; executives of BP, the leaking well's owner, said earlier in the week that such a move could make things worse by damaging whatever part of the blowout preventer was still working.
For now, making the cofferdam work is the priority, said Mark Proegler, a BP spokesman at a command center in Robert, La.
"I have every confidence we'll find a good temporary solution,'' Proegler said, while acknowledging that he could not give a time frame for when another solution could be in place. ``We certainly have every hope and prayer that we find a solution as soon as possible to mitigate the oil flow.''
Eleven people died in the April 20 explosion that wracked the offshore drilling rig Deepwater Horizon and set off the massive leak.
In the weeks since, drifting oil has spurred frenzied preparations from Louisiana to Florida to head off the threat to ecologically fragile marshlands and economically important tourist destinations.
Those preparations continued apace on Sunday, as forecasts from the National Oceanographic and Atmospheric Administration predicted winds would continue blowing the slick west, possibly pushing the oil along the Louisiana shoreline between Timbalier and Barataria bays on Monday and as far west as Point Au Fer Island by Wednesday.
Nineteen ships were plying the Gulf, skimming oil from the surface, and the Coast Guard reported that it had recovered 91,000 barrels of an oil-water mix -- about 10 percent of which is oil -- from the spill.
About 928,000 feet of anti-oil booms have been strung across sensitive areas, and another 1.3 million feet are ready to be put in place, BP said.
The slick is "slowly drifting a little west across the mouth of the Mississippi River,'' Coast Guard Commandant Adm. Thad Allen, whom President Barack Obama appointed to oversee the cleanup effort, said Sunday morning on CBS' Face the Nation. ``But depending on which way the wind blows, it could threaten Mississippi, Alabama and Florida as well.''
In Mobile Bay, authorities were constructing a ``containment gate made with a deep water boom'' to help protect the water there, Allen said.
It was Allen who raised the possibility of using shredded tires and golf balls and other debris to help plug the gusher. He called the strategy a ``junk shot,'' designed to plug the blowout preventer -- the safety mechanism that should have sealed off the well after the April 20 explosion.
"I think I hear an experiment,'' said Robert Bea, an engineering professor at the University of California at Berkeley and oil pipeline expert who spent 18 years with Shell Oil. ``They are pulling every trick known to bring this thing under control.''
On Saturday, BP's chief operating officer, Doug Suttles, said the process of injecting junk into the blowout preventer had ``certain issues and challenges and risks with it.''
On Sunday, Proegler said only that the strategy was ``another backup option. Sub-sea, we're continuing to evaluate ways to overcome the challenges we encountered.''
He said there was no way to estimate when the leak would be contained and that no time has been set for another attempt to place the cofferdam.
"We're trying to move as expeditiously as possible, but as safely as possible,'' Proegler said. ``We have every resource devoted to do this as quickly and safely as possible.''