Rains batter Korea as monsoon season begins in earnest

A sign at the entrance to Cheonggyecheon, a stream in central Seoul, says access is restricted due to risk of flooding amid heavy rainfall Monday morning as the monsoon season starts in Korea. [NEWS1]

Heavy rain fell nationwide Monday as monsoon season began, with the Seoul metropolitan area expected to see up to 100 millimeters (3.9 inches) and landslide alerts issued in Korea’s central and southern regions.

More than 200 millimeters of rain fell in parts of Jeju, where torrential rain began falling Sunday.

Heavy rain warnings were issued in Jeju and southern areas of the mainland and extended to the South Chungcheong and North Jeolla regions early Monday.

Precipitation is expected to range between 50 and 150 millimeters for most of Jeju and from 30 to 100 millimeters for other regions, including the Seoul metropolitan area through Tuesday, according to the Korea Meteorological Administration (KMA). The Gangwon area will receive 10 to 50 millimeters.

Some mountainous regions of Jeju could see more than 300 millimeters of rainfall, and 200 millimeters around the southern coast area, with torrential rain of up to 40 millimeters per hour in the central region and up to 60 millimeters per hour in the southern region.

Seoul likewise saw rainfall during Monday's morning rush hour and downpours throughout the day.

At one point Monday morning, the Seoul Metropolitan Government restricted access to four streams, including Cheonggyecheon and Seongbukcheon, as 10 to 20 millimeters of precipitation per hour fell in the capital area.

Amid the forecasted downpour, the Korea Forest Service announced Monday that it has raised the landslide alert one notch from the lowest “attention” level to the second lowest “caution” out of a four-tier warning scale in the South Chungcheong, North and South Jeolla and South Gyeongsang regions starting 7 a.m.

The forest service urged residents from these provinces to pay attention to emergency disaster text messages and to promptly evacuate to safe locations, such as town halls or schools if a special warning is issued in such landslide-risk areas.

Weather authorities expect up to 120 millimeters of rain will fall in these regions by Tuesday.

This round of monsoon rain is expected to subside from Tuesday afternoon, but more rainfall is expected in many regions later on in the week.

The central and local governments are on alert as monsoon rain began relatively later this year but started with strong downpours from the onset.

Regulations are in place to limit entry into two national parks, Mount Jiri in southern Korea and Dadohaehaesang in South Jeolla, said the Ministry of the Interior and Safety as of 11 a.m. Monday, while seven riverside parking lots and 66 trails were also shut down. Due to the storm, 39 passenger ships were also stranded.

Earlier Monday amid heavier rainfall, access to seven national parks and 277 trails was restricted.

The KMA requested thorough preparations to prevent damage as very strong and heavy rain is expected from the beginning of the monsoon season.

After arriving in Seoul upon completing a weeklong trip to Paris and Hanoi Saturday, President Yoon Suk Yeol ordered Vice Interior Minister Han Chang-seob to “thoroughly prepare for damages from the rainy season,” such as flooding of basement and semi-basement apartments.

Yoon said that with the start of the monsoon season, “preventing casualties is the most important thing, and to do so, prompt warnings and evacuations must be made” according to the presidential office.

He also ordered measures to take care of people with mobility difficulties, such as elderly people living in basement and semi-basement apartments in cities or residents in remote areas who may be isolated if there is flooding.

The presidential office is monitoring monsoon season trends and prevention measures for possible damages from the rain through a meeting of presidential secretaries Monday.

Based on weather data, the central and local governments will predict whether heavy rain will be accompanied by gusty winds, thunder or lightning and prepare in advance for preliminary damage control, focusing on coastal areas, rivers and mountains.

Central and local governments are especially focusing on preventing damage to semi-basement apartments and underground parking lots, which were heavily flooded during the rainy season last year.

The Safety Ministry instructed residents and others to evacuate quickly in the event of flooding, and the public and private sectors are expected to cooperate to help evacuate vulnerable groups such as the elderly and others with reduced mobility.

In a videoconference meeting presided over by Vice Minister Han, attended by heads of the 17 municipal and provincial governments, the ministry also asked local governments to thoroughly prepare for natural disasters such as storms, floods and heat waves in the summer.

The ministry requested local governments to intensively manage 5,600 at-risk areas and ensure that their evacuation plans actually work.

Local governments also plan to dispatch flood prevention supplies such as flood barriers or sandbags.

Another heavy bout of rainfall could affect southern regions around the weekend, with rain clouds concentrating in those areas.

BY SARAH KIM [kim.sarah@joongang.co.kr]