SEOUL, South Korea (CNN) -- Tens of thousands of people returned to their sodden, mud-caked homes around Seoul on Friday after some of South Korea's worst flooding in years. The floods that struck the metropolitan area Thursday after a night of torrential rain killed 131 people, left 61 others missing and caused an estimated $323 million in property damage.
The deluge was brought by the same slow-moving storm system that six days earlier sent flash floods raging down mountain valleys in the southern tip of the Korean peninsula, killing 67 campers and leaving 29 missing and feared dead.
The combined toll of 198 dead and 90 missing from the twin disasters was the worst since a typhoon claimed nearly 350 lives in 1987. As flood waters receded, many of those returning to their homes in Seoul's low-lying suburbs Friday found only shattered wreckage. Many neighborhoods were littered with broken furniture, overturned cars, dead animals and other debris.
The storm dumped up to 62 centimeters (25 inches) of rain around Seoul late Wednesday and early Thursday, one of the heaviest downpours on record.
Rivers overflowed, breaking dikes, sweeping away roads, homes, vehicles and telephone poles and triggering deadly landslides, including one that killed 10 soldiers.
An estimated 20,000 people were left homeless, their dwellings either completely submerged or swept away. Some 55,000 acres of farm land were covered by dark brown flood water.
``Flood waters are retreating fast and people are returning after spending overnight at schools. But the damage was far greater than we first expected,'' said Park Hun, an official at the Home Ministry's Disaster Relief Headquarters.
In a riverside resort town north of Seoul, relief workers working overnight recovered 13 bodies from mudslides that covered bungalows and shops. They were searching for a dozen others who were among the 61 missing.
Mudslides also washed away about 1,300 graves in four municipal cemeteries in Seoul's suburbs. City workers and relatives were trying to collect and identify remains, a doubly dispiriting task in a largely Confucian society that honors its ancestors.
Hardest hit were Uijongbu, Paju, Dongduchon and Kanghwa, satellite cities west and north of Seoul. The rains flooded some of the tributaries of the Han River, which bisects the capital, and the Imjin River, which flows along the border with North Korea.
About 10 tons of mortar rounds, antipersonnel land mines and other ammunition were missing after flood waters swept through an army depot near the border with North Korea, Defense Ministry officials said.
Soldiers with mine detectors were combing the area, but officials feared many of the small, light land mines may have swept downstream.
An unknown number of land mines were also uprooted and swept away along a portion of the demilitarized zone separating South and North Korea. The region was declared off limits. As many as a million mines are believed strewn along the DMZ as a military deterrent.
Operation at Seoul's Kimpo Airport returned to normal Friday, two days after a Korean Air passenger plane skidded off a rain-slicked tarmac, forcing one of the airport's two runways to close. The runway reopened after the plane was towed away.
Weather bureau officials blamed the unseasonal heavy rain -- it should now be the peak of Korea's hot and dry season -- on the "La Nina" weather phenomenon, which is producing unusually wet weather in the Eastern Pacific.