COLUMBIA, S.C. (AP) — The Carolinas saw sunshine Tuesday after days of inundation, but it could take weeks to recover from being pummeled by a historic rainstorm that caused widespread flooding and 17 deaths.

Tuesday was the first completely dry day in Columbia since Sept. 24, but officials warned that new evacuations could be ordered as the huge mass of water flows toward the sea, threatening dams and displacing residents along the way.

"God smiled on South Carolina because the sun is out. That is a good sign, but ... we still have to be cautious," Gov. Nikki Haley said Tuesday after taking an aerial tour. "What I saw was disturbing."

"We are going to be extremely careful. We are watching this minute by minute," she said.

At least 15 weather-related deaths in South Carolina and two in North Carolina were blamed on the vast rainstorm. Six people drowned in their cars in Columbia alone, and several died after driving around safety barriers onto flooded roads.

Flooding is a concern wherever concrete covers soil that would otherwise act as a sponge in heavy rain. The multitude of waterways in the Midlands area — where the Broad and Saluda rivers come together to form the Congaree — made the state capital even more vulnerable.

Now officials are looking with concern to the Lowcountry, where several other rivers make their way to the sea, including the Santee and Edisto. Haley warned evacuations may be needed in several counties toward the coast, and noted that several rivers rising downstream of Columbia worried officials.

"We are seeing some stage of flooding with all of them," she said, adding that none have crested.

Haley said it was too soon to put a price tag on the damage and it could be "any amount of dollars." The Republican governor asked for and received a federal disaster declaration from President Barack Obama, freeing up money and resources for the state.

But South Carolina Sen. Lindsey Graham, a Republican presidential candidate, promised on the Senate floor not "to ask for a penny more than we need" in federal aid, to avoid the "pile-on" seen in some previous disaster aid bills that were used to get financing for unrelated projects.

Water distribution remained a key problem Tuesday across much of the state. In Columbia, as many as 40,000 homes lacked drinking water, and the rest of the city's 375,000 customers were told to boil water before using it for drinking or cooking, an order that Mayor Steve Benjamin said will likely be in effect for "quite some time."

On the campus of the University of South Carolina, there was no floodwater in sight and the dorms had electricity and Wi-Fi. Brennan Maly was able to flush the toilet and use the shower and the university is handing out free bottled water for drinking.

And classes have been canceled for the entire week.

"For the most part, it kind of feels like a very inconvenient way of camping," said Maly, a 20-year-old sophomore. "It's weird. I feel like there's definitely a naive sense of, 'Hey, we don't have drinking water,' while folks down the road are losing their homes."

Authorities have made hundreds of water rescues over several days, pulling people and animals to safety. About 800 people were in two-dozen shelters, but Haley said that number was expected to rise. Some 200 engineers were checking roads and bridges, but about 470 remained closed Tuesday, including a 75-mile stretch of Interstate 95 in the eastern part of the state.

The South Carolina National Guard was trying to bolster a major breech in a waterway near Columbia and working with local officials to try to help keep other smaller dams in the state's flooded regions from bursting.

South Carolina National Guard commander Maj. Gen. Robert Livingston said Tuesday's planned operation involved helicopters dropping 1-ton sandbags from Chinook helicopters on a break between a canal and the Congaree river in Columbia.

"These are big sandbags," the two-star general told reporters at the Emergency Management Division headquarters outside Columbia.

Nearly 30,000 customers were without electricity at the storm's peak, but the power grid is returning to normal, the governor said.

In Effingham, about 80 miles east of Columbia, the Lynches River was at nearly 20 feet on Tuesday, 5 feet above flood stage, the National Weather Service said. A day after evacuation orders went out, Kip Jones paddled a kayak to check on a home he rents out. He discovered that the family lost pretty much everything after seeking shelter elsewhere.

The lower story had almost 8 feet of water in its bathroom and bedrooms, he said.

"Their stuff is floating all in the house," Jones said. "I don't know if the house will be salvageable. ... Once the water comes in the house you get bacteria and you get mold. I don't know if the water in the house is a total loss or a partial. I don't know what to expect. We'll find out soon though."

In Turbeville, Police Lt. Philip Wilkes stood at a traffic stop, telling motorists where they could go and what routes ahead were blocked by flooding or shaky bridges.

No, you can't get to Interstate 95, which was closed, though he said there were hopes it would open later in the day. No, you can't get to Manning about 20 miles away.

"Some people take it pretty good," he said. "Then you've got some of them, they just won't take no for an answer. We can't part the waters."

Much-feared Hurricane Joaquin missed the East Coast, but fueled what experts at the National Oceanic and Atmospheric Administration called a "fire hose" of tropical moisture that aimed directly at the state.

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Contributing to this report were Associated Press writers Bruce Smith in Charleston, South Carolina; Mitch Weiss in Greenville, South Carolina; Susanne M. Schafer, Jay Reeves and Russ Bynum in Columbia; Jonathan Drew in Raleigh, North Carolina; Meg Kinnard in Blythewood, South Carolina, and Seth Borenstein in Washington.