Winds expected to shift and ease in the next few days could buy some time for weather-beaten crews battling to bottle up and burn off a massive slick of rust-colored crude before it fouls fragile marshes and sugary beaches across four Gulf Coast states.

But that brief reprieve could soon send a nasty ripple effect toward South Florida -- pushing outlying plumes of polluted surface water and patches of tar balls into the Gulf of Mexico's powerful loop current. That would propel the mess across the mangrove islands, seagrass beds and coral reefs of the Florida Keys, then up toward Miami Beach, Fort Lauderdale and beyond.

Oceanographers tracking the BP oil slick -- still expanding from an uncapped well belching an estimated 210,000 gallons a day -- said Monday that questions about the loop's impact have increasingly turned from if to when.

Satellite images suggest the loop, which moves seasonally, is creeping north, spinning off small whirls of current that University of Miami oceanographer Nick Shay said may already have drawn in the slick's leading, and lightest, edge.

Robert Weisberg, an oceanographer at the University of South Florida, who updates daily tracking models, pinpoints the loop still about 30 miles south of the slick.

But, he stressed, "The immediacy of the collision of these two features is real. Will it happen in a day, two days, three days, a week, two weeks? I don't know. I'm not willing to say that yet."

For now, the focus of Florida's top political, environmental and emergency managers remains firmly on the Gulf Coast.

Gov. Charlie Crist Monday extended his state of emergency order to 13 more counties, bringing the total to 19, as the spreading oil slick threatened Florida's coast.

"It is an enormous mess," Crist said. "It is unbelievable, the magnitude of this thing. Clearly every effort needs to be put on plugging the hole up and stopping the bleeding."

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