Adm. Thad Allen, who also is overseeing the national effort to contain the devastating spill, made the remarks Saturday afternoon during a teleconference.
One expert has said the spill's surface area has at least tripled in size in just a day or so.
The Wall Street Journal reported Friday ($) that industry experts estimate that as much as 25,000 barrels of oil per day could be emptying into the Gulf - five times the current estimate.
Experts also have cautioned that if the spill continues growing unchecked, sea currents could suck the sheen down past the Florida Keys and then up the Eastern Seaboard.
The sheen already has reached into precious shoreline habitat and remains unstopped. That has raised fears that the ruptured well could be pouring more oil into the gulf than the 200,000 gallons per day initially estimated.
On CBS' "The Early Show" Saturday morning, Allen said that heavy winds are affecting cleanup efforts.
"It's always a huge factor - Mother Nature gets a vote in these responses," Allen said. "Since the start of this oil release, the winds shifted around approximately 270 degrees around the compass, and it makes it very difficult for spill trajectory. But if it really starts kicking up, boom becomes ineffective."
Frustrated fishermen eager to help contain the spill from a ruptured underwater well had to keep their boats idle Saturday as another day of rough seas kept crews away from the slick, and President Obama.
Documents also emerged showing BP PLC downplayed the possibility of a catastrophic accident at the offshore rig that exploded. BP operated the rig, which was owned by Transocean Ltd.
How far the spill will reach is unknown, but the sheen already has reached into precious shoreline habitat and remains unstopped, raising fears that the ruptured well could be pouring more oil into the gulf than estimated.
The Coast Guard has estimated that about 200,000 gallons of oil are spewing out each day - which would mean 1.6 million gallons of oil have spilled since the April 20 explosion that killed 11 workers. The environmental mess could eclipse the Exxon Valdez disaster, when an oil tanker spilled 11 million gallons off Alaska's shores in 1989.
The slick nearly tripled in just a day or so, growing from a spill the size of Rhode Island to something closer to the size of Puerto Rico, according to images collected from mostly European satellites and analyzed by the University of Miami.
On Thursday, the size of the slick was about 1,150 square miles, but by Friday's end it was in the range of 3,850 square miles, said Hans Graber, executive director of the university's Center for Southeastern Tropical Advanced Remote Sensing. That suggests the oil has started spilling from the well more quickly, Graber said.
"The spill and the spreading is getting so much faster and expanding much quicker than they estimated," Graber told The Associated Press on Saturday.
Louisiana State University professor Ed Overton, who heads a federal chemical hazard assessment team for oil spills, cautioned that the satellite imagery could be deceiving.
He said satellites can't measure the thickness of the sheen and makes it difficult to judge how much oil is on the water.
Another issue is that the oil slicks are not one giant uniform spill the size of an island. Instead, they are "little globs of oil in an area of big water," Overton said.
The Florida Keys are home to the only living coral barrier reef in North America, and the third largest coral barrier reef in the world. About 84 percent of the nation's coral reefs are located in Florida, where hundreds of marine species live, breed and spawn.
"If it gets into the Keys, that would be devastating," said Duke University biologist Larry Crowder.
Ian R. MacDonald, an oceanography professor at Florida State University, said his examination of Coast Guard charts and satellite images indicated that 8 million to 9 million gallons had already spilled by April 28.
Alabama's governor said his state was preparing for a worst-case scenario of 150,000 barrels, or more than 6 million gallons per day. At that rate the spill would amount to a Valdez-sized spill every two days, and the situation could last for months.
"I hope they can cap this and we talk about 'remember back when,"' Gov. Bob Riley said late Friday, "but we are taking that worst-case and building barriers against it."