The remnants of Hurricane Ivan spawned severe weather across much of the southeastern United States today, unleashing heavy rains, flooding and tornadoes that threatened communities from the Carolinas to the Washington suburbs.

In the Washington area, the National Weather Service issued a series of tornado warnings into the night as possible twisters uprooted trees, clipped power lines and damaged houses and other buildings.

There were no immediate reports of injuries from the possible tornadoes, including one in Centreville seen on radar images and in local TV news video near Interstate 66 and Route 28 at the height of the evening rush hour.

A pair of likely tornadoes also was spotted near Sterling, the weather service reported. Other possible tornadoes were reported near the city of Manassas and near Poolesville in Montgomery County. Yet another system produced two possible tornadoes near Quantico, the weather service said.

The weather service extended a tornado watch for the entire Washington area until midnight.

Fairfax County police spokeswoman Mary Ann Jennings said the hardest-hit part of the county appeared to be the Centreville and Chantilly areas, where two homes were seriously damaged but no one was hurt.

At Dulles International Airport, workers were briefly evacuated from the air traffic control tower shortly after 6 p.m., when a funnel cloud was spotted approaching the airport, said Jonathan Gaffney, spokesman for the Washington Metropolitan Airports Authority.

Gaffney said people inside the terminal were told to move away from the large glass windows and flights were grounded until about 6:45 p.m. One pilot awaiting takeoff at a gate evacuated passengers as a precaution, he said.

In Loudoun, sheriff's deputies said a house in a Hamilton subdivision had its windows sucked out. Elsewhere in the county, the animal shelter in Waterford was struck by lightning. At Leesburg Airport, one rental hangar and a plane were burned in a two-alarm fire that started after the storm hit.

Flood watches also were in effect for the District, Virginia and Maryland, with forecasters cautioning that the combination of tropical moisture from Ivan and a slow-moving cold front would produce heavy rain from late tonight through Saturday. The predicted rainfall of four to seven inches could lead to major flooding at some points on mainstream rivers, including the Potomac Basin, the weather service said.

The warnings and watches came as Ivan, now classified as a tropical depression, left a trail of devastation across a vast swath of the Southeast.

Another worry, at least for residents of Gulf Shores, Ala., was a 12-foot-long, 1,000-pound alligator named Chucky -- missing since the hurricane blew down the fence surrounding his pond at the Alabama Gulf Coast Zoo and turned parts of the area into a vast lake. Zoo officials said Chucky, the biggest of several gators that slipped away during the hurricane, might be hungry by now, and they were warily looking for him.

According to the National Hurricane Center, Ivan was centered about 100 miles southwest of Roanoke, Va., as of 5 p.m., with sustained winds near 20 mph. It was moving in an east-northeasterly direction at about 20 mph.

The storm's heavy rains prompted flood watches for the entire Appalachian chain and territory to the north and east.

Flood warnings were issued for portions of Alabama and Georgia, the eastern parts of Tennessee, Kentucky and Ohio, as well as West Virginia, Virginia and Pennsylvania.

Tornado watches covered Maryland, West Virginia, Virginia and North Carolina.

In Virginia, chainsaw units, swift water rescue crews, the state police and the National Guard were mobilized this afternoon as Gov. Mark R. Warner (D) declared the third state of emergency in three weeks.

Heavy rainfall was expected to continue across Virginia into Saturday, causing flooding in low-lying areas and near waterways. Officials also warned of flooding in spots where it doesn't normally occur because of drenched grounds and they warned that the downpours would cause mudslides in areas with steep terrains. State officials urged drivers not to cross highwater.

Flood waters inundated some Tennessee and North Carolina towns, and nearly 4 inches of rain hit Asheville, N.C. Elsewhere in western North Carolina, as must as 8 inches of rain fell, and more than 100 roads were closed by flooding or fallen trees.

Three storm-related deaths were reported in North Carolina -- two when a house collapsed in Macon County and another when a tree fell on a home in Henderson County, the Associated Press reported.

That brought Ivan's death toll to 28, according to the AP's tally: 14 in Florida, three in Mississippi, three in Georgia, one in Alabama, three in North Carolina and four in Louisiana. The victims in Louisiana were seriously ill patients who died after being evacuated from their storm-threatened homes.

Before reaching the U.S. Gulf Coast early Thursday, Ivan caused the deaths of at least 68 people in the Caribbean.

By the hurricane center's account, it was the deadliest hurricane to hit the United States since Hurricane Floyd left 56 people dead in 1999.

More than 1.1 million people in five states were still without power today because of Ivan's damage.

After losses of up to $11 billion from two preceding hurricanes -- Charley and Frances -- the damage to insured property alone from Ivan was expected to add billions of dollars more to this hurricane season's bill.

Some of the heaviest property damage was to houses, condos and businesses along the Alabama and Florida Panhandle Gulf Coasts, where Ivan's winds ripped away facades, tore off roofs and completely wiped out some structures.

Today, residents of the Florida Panhandle -- many of them unshowered and unshaven and living in darkened motel rooms or homes with no phone service or running water -- struggled to find some normalcy.

Throughout the morning and into the afternoon, the sun beamed bright and hot in a cloudless blue sky, while below, across mobile home parks, residential streets and rural pockets, wreckage was everywhere. Old oak trees lay across roads and on top of homes and businesses.

People sat in their cars in gas station parking lots, hoping to be the first in line when, and if, the power came on. The few businesses able to open were packed with customers.

At a Tom Thumb gas station and convenience store in Pace, a small Panhandle town in rural Santa Rosa County, manager Sheila Colwell poured hot water into her two coffee-makers, which she set outside the store. The water was boiled in pots on a propane barbecue grill she put near the front entrance.

"We're barbecuing water," she said.

Locals and travelers walked in, asking directions, or looking for snacks and a cold, or somewhat lukewarm, drink.

"We've been open from daylight to dark," said Colwell, 39. "Anything that's not nailed down is for sale."

Colwell lost the two aluminum canopies over her pumps, and her front sign above the door blew down. But she thought it was important to stay open for her customers.

"I was worried about you," she said as she hugged a customer and friend. The customer was looking for bread because she said hers was wet from the rains, but Colwell said it would take about an hour for a delivery to come from another store.

Pensacola remained in the dark ages today, without power, water or phone service in the aftermath of Ivan. Bridges were closed, giving this Panhandle town of 56,000 a sense of isolation. Residential streets and interstates were still littered with tree limbs and power lines. National Guard troops in green camouflage uniforms drove through the streets in Humvees and directed traffic at major intersections.

Officials said the regional airport, city hall and two hospitals were damaged in the storm. Scores of damaged homes and collapsed buildings -- some with fallen trees through the roofs, others with signs and entire walls blown out -- could be seen throughout town, and officials were still assessing the scope of the damage today.

Escambia County officials said they were investigating seven storm-related deaths since Wednesday evening, when Ivan's winds began to rake the area in advance of its center's landfall early Thursday.

The National Hurricane Center, meanwhile, issued new advisories about two other tropical storms that could become hurricanes, Jeanne and Karl.

Jeanne's winds weakened to 50 mph as it crossed the island of Hispaniola, but the storm could strengthen again over water in the next day or so as it makes its way along the Bahamas toward the southeastern U.S. coast, the center reported.

Tropical Storm Karl, located more than 800 miles west-southwest of the Cape Verde Islands and headed toward the west-northwest, is expected to become a hurricane in the next 24 hours, the center said.

Fernandez reported from Alford, Fla. Staff writers Tom Wilkinson, Maria Glod, Steven Ginsberg and Mark Stencel contributed to this report.