Heavy rainfall across the country over the past few days has killed at least 30, with more likely casualties as 12 people are still unaccounted for, as a typhoon is approaching the peninsula.

The unusually long and intense downpour, which started on Aug. 1, has triggered flash floods and landslides, resulting in the deadliest monsoon season in nine years. Officials scrambled to lend more support and expedite recovery, with some politicians voicing the need for another supplementary budget to help cope with damages.

Seoul, Gyeonggi and Gangwon and Chungcheong provinces were hit by heavy rains earlier last week which gradually expanded to the provinces of North and South Jeolla on Friday and Saturday.

From Friday to Sunday morning, all regions except Jeju Island were hit with as much as 612 millimeters of rain, according to the Korea Meteorological Administration.

The Korea Forest Service on Sunday issued the highest level of landslide warning for the entire country except Jeju, as soil density and strength have weakened from continued rain. Flood warnings have been imposed on vulnerable areas near swollen rivers and streams.

As the downpour continued on its ninth day, casualties and property damages surged.

According to the Central Disaster and Safety Countermeasure Headquarters, close to 6,000 people from 3,489 households were forced to evacuate, and 4,617 people have yet to return home. With the Seomjin River flooding in South Jeolla Province, 3,749 people from 2,205 households stayed at schools, community centers and gymnasiums on Saturday.

At the same time, 9,491 damages have been reported, with 4,234 involving private property. The downpour also flooded 9,317 hectares of farmland while bombarding 2,572 residential buildings and 1,344 barns and storage facilities.

A total of 118 roads and passes have been restricted to traffic, with some trains suspended. Ten flights have also been canceled as the runway at the Gwangju Airport, and 523 tracks at 20 national parks have been barred access.

Casualties from the torrential rains stood at 30 people dead, eight injured and 12 missing as of 6 a.m. Sunday. No additional casualties have been reported as of press time.

Sunday’s death count was up by two from a day earlier as two men were found dead after a landslide in Jangsu, North Jeolla Province. The number of missing rose by one from Saturday after a 70-year-old man was swept under a stream in Damyang, South Jeolla Province.

The latest downpour has raised the number of deaths from this year’s monsoon season to a total of 50 dead or missing, the highest figure in nine years since 2011 when 78 people died or went missing. This year’s figure is a compilation of all casualties reported since the country officially entered the monsoon season on June 24.

As more rain is expected this week with a typhoon approaching the peninsula, this year’s rainfall could set a new record as the longest. In 2013, Korea experienced 49 days of monsoon season.

Typhoon Jangmi, the fifth typhoon of this year, is expected to bring heavy volume of rain clouds from the south and is advancing with 18 meters per hour of speed toward west of Japan.

The national weather agency said Jangmi, which would be the first typhoon of this year to directly impact Korea, is expected to arrive near Jeju on Monday morning and later advance to the south coast in the afternoon.

The typhoon is expected to bring another heavy downpour, especially in South Gyeongsang Province and Jeju Island. The weather agency said the regions could be hit with up to 300 millimeters of rain due to the typhoon.

Jangmi is expected to travel out to the East Sea on Monday night and gradually weaken, but the KMA said it could fade away quicker than original forecast as the typhoon has already started weak. Even after the typhoon leaves the peninsula, the weather agency forecasts rainfall will continue until Tuesday.

As implications for additional casualties and property damages become clear, the government and officials are engaged in emergency recovery efforts while preparing for the next round. The central disaster response team said emergency recovery work on damaged properties and roads is around three-quarters complete.

The government on Friday declared it has designated seven hard-hit areas as special disaster zones, allowing them to receive state aid and other necessary support. Officials are reviewing to declare designations for more areas upon requests from district and municipal officials.

The extreme weather prompted Defense Minister Jeong Kyeong-do to cancel their vacation plans, becoming the latest leader to do so after President Moon Jae-in, Prime Minister Chung Sye-kyun and Gyeonggi Province Gov. Lee Jae-myung.

By Ko Jun-tae (ko.juntae@heraldcorp.com)