In July 2011, Seoul was hit by the heaviest rain in a century. Subway stations were closed, tree trunks were ripped from their roots and roads became rivers.

The worst came in the early morning of July 27, when a huge landslide swept through one of Seoul’s most affluent areas.

The wall of mud and water from Mount Umyeonsan in southern Seoul took the lives of 16 people. Hundreds of residents had to rush outside, puzzled.

“‘I’ll be right back’ was the last words I heard from him,” Kim Il-young, 56, who lost her husband that day, told The Korea Herald. 

Minutes before the collapse, Kim’s husband went outside to check on a container box containing tools the two were going to use for their new business the next month.

“The landslide took my husband’s life, our 30 years of marriage and hopes for the future after a series of business failures.”

Since May 1, several bereaved family members including Kim have been taking turns standing in silent protest in front of Seoul City Hall, holding a sign board that reads, “Reinvestigation on Umyeon landslides.”

“Even today I can’t imagine how such a huge natural disaster could happen in Seoul. But city and district officials are all playing the blame game, saying this was no man-made disaster, but part of the unavoidable vagaries of nature, or an act of God,” she said.

At least four major development projects took place on the mountain in the 2000s alone, including Umyeonsan Tunnel, Mount Umyeonsan Natural Ecological Park, Gangnam Beltway Tunnel and Mount Umyeonsan Dullegil, a hiking trail.

Lee Chang-woo, researcher at the Korea Forest Research Institute, believes everyone is partly to blame.

“It all began from our ignorance ― ignorance of urban landslides and that such danger is always next to us even in a clean, organized city,” Lee explained.

“People develop, exploit and climb mountains to enrich their lives. Although such activities have improved our quality of life, land development has become one of the biggest factors for natural disasters.”

Lee pointed out that Korea had to face huge losses of both life and property over time because adjacent areas were turned into residential ones, and the catastrophic landslides two years ago gave experts a new task.

“People just call it a landslide if soil or rock roll down from mountains. But landslides from grading, terrain cutting and filling, and excessive development are normally differentiated from, and worse than natural ones,” said Yoo Chul-sang, professor at Korea University’s School of Civil, Environmental and Architectural Engineering.

Mount Umyeonsan is not the only mountain that is marked red on the landslide hazard map provided by the Korea Forest Service, denoting the highest level of risk.

About 64 percent of South Korean land is mountainous, meaning that the country is prone to natural disasters caused by inherent factors such as the depth and density of soil, combined with external ones like earthquakes and heavy rain.

Lee says the country could face bigger, stronger landslides considering the changing patterns of rainfall.

“South Korea’s precipitation rate is expected to increase an average of 1.79 millimeters each year until 2100. That’s 161 millimeters in just 90 years,” the researcher noted.

Landslide hazard zones will be expanded nationwide, especially in the south, he added.

In fact, the deterioration is already in progress. In the 1980s, 231 hectares of forest were ruined by landslides. The figure rose to 349 in the 1990s and soared to 713 in the 2000s.

During the period, the precipitation rate steadily increased, registering 301.5 millimeters in the single day of the Mount Umyeonsan incident.

“There are many preventive measures but many of them are limited to rural areas where it is easy to install structures around mountains. What’s important is to help trees fix their roots firmly into the ground so they can endure landslides.”

Some experts claim that concrete city surfaces and the centralized processing of sewage contributed to the landslide two years ago.

“Soil permeability has dropped sevenfold over the past four decades, enhancing the risk of flooding and even dry streams in the long term,” professor Yoo said.

Rainfall, flooding and landslides are rising to the fore again this summer, as the central part of the peninsula, especially Seoul, Gangwon Province and northern Gyeonggi Province, have been pounded with heavy rains since July 11.

Six notable landslides occurred on the Joongang Expressway, some of them blocking the road for hours with 200 tons of earth and sand.

“There is no safe place. How are we supposed to feel secure even when we’re at home? Koreans are way too ignorant about safety issues and it is about time to change that,” Kim said.

“Sprawling developments should be controlled and should always be accompanied by preventive measures before construction.”

By Suk Gee-hyun (monicasuk@heraldcorp.com)