(CNN) The rain may have stopped, but South Carolina is grappling with a host of new concerns. Dam breaks. Billions of dollars in damage. And rivers that still haven't crested.
"We still have to be cautious," Gov. Nikki Haley told reporters on Tuesday afternoon. "The next 36 to 48 hours are going to be a time that we need to continue to be careful."
Haley declined to provide an estimated cost of the damage -- which she called "disturbing" -- but said state and Federal Emergency Management Agency officials were making assessments.
"It's hard to look at the loss we're going to have," she said. "This could be any amount of dollars."
More than 400,000 state residents were under a "boil water advisory" affecting about 16 water systems, said Jim Beasley, a spokesman for the S.C. Emergency Response Team.
South Carolina flooding: 'We have lost everything'
Here's the latest on the mammoth flooding in the region:
Dam breaks
At least 11 dams have failed in South Carolina since Saturday, the state's Emergency Management Division said. Another 35 dams were being monitored.
One failure, of the Overcreek Bridge dam in Richland County's Forest Acres, sent a torrent of floodwater raging downstream and forced evacuations near Columbia.
Officials allowed water to breach at least one other dam, also in Richland County. Officials conduct these controlled breaches "to prevent a much larger incident and a much larger amount of water escaping from the dam," emergency management spokesman Derrec Becker said.
Haley said National Guard members were helping with sandbagging operations and other mitigation efforts.
Death toll rises
Devastating hurricanes of the last 30 years
The last 30 years have brought plenty of deadly and destructive storms to the United States, including 2005's Hurricane Katrina (here, police and others use boats to rescue people in a flooded New Orleans neighborhood). Click through the gallery to see more photos of disastrous hurricanes over the last three decades, and
check out this video to find out which states have been hit the most often.
Sandy, 2012: It technically lost its hurricane status shortly before striking New Jersey, but its gigantic size -- it covered 1.8 million square miles at landfall -- sent devastating storm surges to the coast. Here, a man looks for pieces of his beach house after
Sandy demolished it in Seaside Heights, New Jersey. With 72 directly killed in eight states, this was the most deadly tropical cyclone outside the South since 1972's Hurricane Agnes. At least 650,000 U.S. homes were damaged or destroyed in the U.S.
Irene, 2011: After hitting North Carolina,
Irene did most of its damage in the way of heavy rain and flooding in New York and New England. In southern Vermont alone, nearly 2,400 roads were damaged or destroyed, NOAA says. Here, Tony Carr carries a TV set September 1 from his home, which was destroyed by Irene-related floods in Prattsville, New York.
Ike, 2008: After killing scores in the Caribbean, Ike turned to Texas, sending storm surges that leveled homes on Galveston Island. It's remnants did extensive damage as far north as Ohio, where 2.6 million people lost power. Here, an Air Force Reserve pararescueman scans the ravaged Texas landscape shortly after Ike.
Katrina, 2005: Unforgettable
Katrina -- the costliest hurricane and one of the five deadliest to hit the United States, according to NOAA -- devastated the Gulf Coast days after crossing Florida. Flooding destroyed thousands of homes in the New Orleans area alone; storm surges wiped out coastal towns in Mississippi. Here, people stand stranded on a roof in New Orleans.
Rita, 2005: Just a month after Katrina,
Hurricane Rita piled on, slamming into the Louisiana coast. Wind, rain and tornadoes left billions in damages from eastern Texas to Alabama. Here, surging water from Rita reach the streets of New Orleans' Ninth Ward, topping a levee that had just been patched after Katrina damaged it.
Wilma, 2005: The year might be remembered for the one-two punch of Katrina and Rita, but
Wilma, which hit Florida after devastating Mexico's Yucatan Peninsula, would become (as of May 2015) the U.S.'s fifth most costly cyclone. Here, workers remove debris from a Miami flower and plant shop on October 28. Millions were without power in the state.
Beta, 2005: Beta wasn't one of the most devastating cyclones, but we include it here to make a point: There were so many named storms in the Atlantic in 2005 that forecasters' pre-approved 21-name list for the year was exhausted. So they went to the Greek alphabet six times, including for Hurricane Beta, which directly hit part of Nicaragua. Here, people wade through a street flooded by Beta in Honduras on October 30.
Ivan, 2004: This year also was hurricane-heavy, punctuated by
Ivan, a storm with two lives. First, it killed dozens in the Caribbean and slammed into Alabama. Later, its remnants went back over Florida from the Atlantic and re-formed in the Gulf as a tropical storm, making another landfall in southwestern Louisiana. It spawned more than 100 tornadoes, one of the factors that left considerable damage across the Southeast and some mid-Atlantic states. Here, a woman walks over debris as she visits her home, destroyed by Ivan, in Perdido Key, Florida, on September 20.
Floyd, 1999: Deadly flooding, especially in North Carolina, was one of Floyd's main legacies. Parts of eastern North Carolina and Virginia received 15 to 20 inches of rain, and flooding led to the razing of thousands of buildings -- most of them homes -- from North Carolina to New Jersey. At the time, it was the deadliest U.S. hurricane since 1972. Here,a beach house, severely damaged by Floyd, sits crumbled sits in the sand on the Oak Island town of Long Beach, North Carolina, on November 10.
Andrew, 1992:
Andrew blasted its way across south Florida on August 24 as a Category 4 with peak gusts measured at 164 mph. After raking entire neighborhoods in an around Homestead, it moved across the Gulf to hit Louisiana as a Category 3. It was responsible for 23 U.S. deaths and three in the Bahamas. Here, a sailboat sits on a sidewalk at Dinner Key in Miami after Andrew washed it ashore.
Hugo, 1989:
Hugo ripped through the Carolinas, starting with Charleston, South Carolina, on September 22 as a Category 4 after raking the U.S. Virgin Islands and Puerto Rico. Here, a man stands in a destroyed house on September 27 in South Carolina.
So far, at least 17 people have died in weather-related incidents: 15 in South Carolina and two in North Carolina.
At least nine people drowned and six died in traffic accidents, South Carolina's Department of Public Safety said.
North Carolina reported two deaths from traffic accidents, in Cumberland and Jackson counties, a state emergency management spokeswoman said.
Haley said there had been 175 water rescues so far in South Carolina, and more than 800 people were temporarily housed in shelters.
More than 70 miles of Interstate 95 in the state remained closed, with five to eight bridges still awaiting structural checks, she said.
2015 Atlantic hurricane season fast facts
Caskets float away
Of all the scenes of items drifting away in the flooding, perhaps none appeared as dramatic as a casket unearthed from a cemetery.
Wayne Reeves, pastor of New Life Ministries in Summerville, was in the middle of an interview when he saw the casket float away.
So he headed into the waist-deep floodwater to retrieve it.
"That's somebody's family out there," he told CNN affiliate WCBD-TV. "That's (a) family suffering. That's their family there that popped up from under the ground. And I think it's the human thing to do."
The casket, still adorned with white and pink flowers, carried the remains of a woman buried in May, WCBD said. Another casket, that of the woman's husband, also drifted away, but Dorchester County sheriff's officials later recovered it.
As it turned out, the woman's family was watching nearby as Reeves went into the water.
"This family don't want to sit on the edge of this road all night long watching their family members bob in the water like that," the pastor told WCBD.
"If that was my mom or my dad, I'd walk through hell and high water. And today it happened to be high water."
South Carolina flooding: How to help
Apartments looted
Some Columbia residents left their homes as victims of flooding. They returned to find their homes looted.
Storms flood East Coast
This aerial photo shows flooding around Aberdeen Country Club in Longs, South Carolina, on Tuesday, October 6. South Carolina experienced record rainfall amounts over the weekend, forcing hundreds of evacuations and rescues.
A woman uses her boat to check on neighbors and see if they want to evacuate in Summerville, South Carolina, on Monday, October 5.
Police officers carry a woman to dry land after she was rescued from her home in the St. Andrews area of Columbia, South Carolina, on October 5.
Neighbors and friends help clean up a home affected by flooding in Columbia on October 5.
Five-month-old Jeremiah Odum, left, and his 2-year-old brother, Braxton Odum, nap on a cot in a high school gymnasium being used as a Red Cross shelter for flood evacuees in Rowesville, South Carolina, on October 5.
Rescue teams wait for an emergency vehicle in the Forest Acres neighborhood of Columbia on Monday, October 5.
An oil sheen floats atop floodwater in a subdivision west of the Ashley River in Charleston, South Carolina, on October 5.
A dog is cut off from its home in Florence, South Carolina, on October 5. Florence is about 85 miles east of the capital city, Columbia.
Hunter Baker drives his boat down a flooded East Black Creek Road to his home following heavy rains in Florence on October 5.
A man makes his way through floodwaters in the parking lot of The Citadel Beach Club on Isle of Palms, South Carolina, on October 5. Charleston and surrounding areas are still struggling with flooding, as are areas 100 miles inland.
Members of Norfolk Fire-Rescue pull a man from his car in Norfolk, Virginia, on Sunday, October 4.
David Linnen takes a yard rake to clear drains in front of the Winyah Apartments in Georgetown, South Carolina, on October 4.
Charlene Stennis is escorted to safety after her son was rescued from a stranded vehicle during the heavy rains on October 4 in Columbia, South Carolina.
The roof of a submerged vehicle peeks above the flood waters on October 4 in Columbia, South Carolina.
Tripp Adams, 8, walks through flood waters in Georgetown, South Carolina, on October 4.
A person walks through the flooded Market and Water streets in downtown Wilmington, North Carolina, on October 4.
Neighbors watch employees with the city of Isle of Palms, South Carolina, cut a live oak tree that fell after heavy rain on October 4.
A man watches as a vehicle tries to navigate flood waters in Florence, South Carolina, on October 4.
Two men row a boat on a flooded street in downtown Charleston, South Carolina, on October 4.
Police block an entrance to Highway 17 in Charleston, South Carolina, on October 4.
A man paddles up to a flooded store in Columbia, South Carolina, on October 4.
A firefighter walks down a flooded street in downtown Charleston, South Carolina, on October 4.
A worker cleans a drain on a flooded street in downtown Charleston, South Carolina, on Saturday, October 3.
A utility worker examines the damage to a home Charlotte, North Carolina, on October 3.
A motorist turns back as floodwater rises in Harrisburg, North Carolina, on October 3.
A woman walks through One City Plaza in downtown Greenville, South Carolina, as rain and wind pound the area on October 3.
Bob Ashbaugh, from Pittsburgh, takes video of waves crashing over homes at risk from erosion during high tide in Isle of Palms, South Carolina, on October 3.
Stuart Tait ties together wood after his house collapsed into an inlet on Grassy Sound during high tide on October 3 north of North Wildwood, New Jersey.
Will Cunningham, 14, rides his bike down Station 29 on Sullivan's Island, South Carolina, ahead of his paddling friend Patrick Kelly, 14, on October 3.
Paul Banker paddles a kayak as his wife, Wink Banker, takes photos on a flooded street in Charleston, South Carolina, on October 3.
Up to 4 inches of rain could strike the waterfront between Georgia and New Jersey. Motorists deal with the conditions on Friday, October 2, in Seaside Heights, New Jersey.
Workers install a flood barrier at the entrance to the Market Pavilion Hotel in downtown Charleston, South Carolina, on Friday, October 2. Parts of the South Carolina coast braced for likely flooding.
Flooding engulfs a neighborhood in the Strathmere section of Upper Township, New Jersey, on October 2.
Sandbags surround a building in Old Town Alexandria, Virginia.
A man closes a storefront on October 2 in Seaside Heights, New Jersey.
Floodwater rises along Central Avenue in Sea Isle City, New Jersey, on October 2.
Cars negotiate flooded streets on October 2 in Midland Beach on Staten Island, New York.
On Sunday, an apparent dam breach led to the flooding of the Willow Creek Apartments, property manager Heather Lovell told CNN affiliate WACH-TV.
So rescue crews in boats came to the complex and helped residents to safety.
On Monday, Pamela Courts returned to her apartment and found not just flood damage but signs of theft.
"Overnight, we had a break-in, so whatever was upstairs they came and took: TVs, jewelry, everything," she told WACH.
Resident Juamaame Evins told the affiliate he was trying to stay positive despite the back-to-back hardships.
"Even though we lost everything and stuff got stolen, we can rebuild together and help each other and be each other's backbones and carry each other through this time because we need each other," he said.
Graham opposed Sandy aid but wants help in South Carolina
Rivers still rising
The flooding is far from over. Rivers might not crest for another two weeks, CNN meteorologist Chad Myers said.
And the mayor of Columbia, who has said he believes damage "will probably be in the billions of dollars," is bracing for more trouble.
"We aren't close to being out of the woods," Mayor Steve Benjamin said Tuesday, adding that even more dams could be in danger of breaking or being topped by water. "We still expect the water to start coming down from the Upstate, coming downhill to the Midlands."
The situation is the result of a weather system that funneled tropical moisture into South Carolina last week and refused to move on, Myers said.
"It was a garden hose that just kept pouring ashore in one spot, and that spot was South Carolina," he said.
Flooding conditions could force the South Carolina Gamecocks to move Saturday's game against Louisiana State University to Baton Rouge, University of South Carolina Athletics Director Ray Tanner said. The school hopes to make a decision in the next day or two.
The University of South Carolina has canceled classes through Friday, saying that resuming normal operations for its 34,000 students and 6,000 faculty would "place an undue burden on a recovering infrastructure in the city."
Al Roker apologizes after outrage over South Carolina flood selfie
CNN's Tina Burnside, Michael Pearson, Dave Alsup, Jeremy Grisham, Sam Stringer, Tony Marco and Shawn Nottingham contributed to this report.