Extreme Weather and Weathered Soil Cause Landslide on Bocimi Toll Road

The landslide on the Bocimi Km 64 Toll Road in Sukabumi Regency was triggered by a combination of extreme weather and weathered soil conditions.

KOMPAS/RONY ARIYANTO NUGROHO

The condition of the toll road that collapsed in Bogor Ciawi Sukabumi (Bocimi) at km 64 in Purwasari Village, Cicurug, Sukabumi Regency, West Java, on Thursday (4/4/2024).

BANDUNG, KOMPAS — The Bogor-Ciawi-Sukabumi or Bocimi Toll Road collapsed at Kilometer 64+600 in Sukabumi Regency, West Java, on Wednesday (3/4/2024) evening. The incident was triggered by extreme weather in the form of rain that hit the area for the last three days and weathered soil conditions.

West Java Climatology Station forecaster, Perdana Usior, Thursday (4/4/2024), said that before the landslide occurred on the Bocimi Toll Road, , it rained with very heavy to extreme intensity. This is known based on interpretation of radar images and rain measurement data closest to the affected location.

"Based on the monitoring results, there has been rain for three consecutive days. This condition can cause the soil to become more unstable and increasingly prone to landslides," explained Perdana.

Perdana explained that there are several phenomena that support the potential growth of convective clouds in some areas of West Java, especially in Sukabumi Regency. These factors include, among others, relatively warm sea surface temperatures that drive the increase in water vapor.

Also read: The Bocimi Toll Road has not been inaugurated a year since the President collapsed, two people were injured

KOMPAS/RONY ARIYANTO NUGROHO

A landslide occurred on the embankment of the Bogor-Ciawi-Sukabumi (Bocimi) toll road at Km 64 in Purwasari Village, Cicurug, Sukabumi Regency, West Java on Thursday (4/4/2024).

The next factor, according to Perdana, is the humidity of the air in the range of 55 to 98 percent and the atmospheric instability index which falls under the category of moderate to strong instability in some areas of West Java. This condition has the potential to increase the activity of convective cloud growth.

Head of the Jabar Climatology Station, Rakhmat Prasetia, urges the community to be vigilant about the occurrence of extreme weather in the form of moderate to heavy rain accompanied by lightning and strong winds in the evening. This condition is triggered by a rise in hot air temperatures between 10.00 am and 2.00 pm.

Also read: Bocimi Toll Road Closed due to Landslide, This is the Route that Can Be Used

Rakhmat revealed that before the occurrence of extreme weather, cumulonimbus clouds will appear. These clouds are dark and soar high like cauliflower.

"It is estimated that the potential for rain accompanied by lightning and strong winds with short duration from noon to night will occur for the next three days. This phenomenon is happening in some areas in Bogor regency, Sukabumi regency, and Depok city," he said.

KOMPAS/RONY ARIYANTO NUGROHO

The situation of the toll road surface that collapsed at Bogor Ciawi Sukabumi (Bocimi) Toll Road Km 64 in Purwasari Village, Cicurug, Sukabumi Regency, West Java, on Thursday (4/4/2024).

Weathered soil

The head of the Center for Volcanology and Geological Disaster Mitigation (PVMBG), Hendra Gunawan, explained that the ground movement that caused damage to the toll road section occurred in an area with a fairly thick weathered soil and steep slope. This condition puts the area in a potential zone for medium to high ground movement.

"The disaster-prone area is predicted to be within the boundary of the youngest rock deposits of Mount Pangrango's volcanic rocks, including lahar and andesite layers. In this zone, landslides may occur if the rainfall exceeds normal levels," he said.

Landslides on this section of road resulted in three vehicles having accidents.

As a preventive measure, according to Hendra, the community is asked to be more cautious, especially residents who live around the area and road users who cross the region. Socialization to the community is also needed so that they are more aware and cautious in facing landslides and soil movements.

"Activities that disturb the stability of slopes, such as slope cutting, tree felling, and pond construction, should not be carried out. If cracks appear, they should be immediately covered with soil and compacted to reduce water absorption. Residents, officials, and teams on duty are always vigilant in anticipating subsequent landslides, especially during the rainy season," he said.

GOOGLE STREET VIEW

The Bogor-Ciawi-Sukabumi tol (highway) or Bocimi around Kilometer 64 in Sukabumi Regency, West Java, as seen through Google Street View.

Deputy Director of Traffic at West Java Regional Police, Adjunct Commissioner General Edwin Affandi, revealed that the Bocimi toll road, especially Section 2, is still closed until now. This is because the road retaining wall foundation is located on unstable ground.

"A landslide on this section of road resulted in three vehicles having an accident. "Two people were injured in this incident," said Edwin.

Also read: Bocimi Km 64 Toll Road Landslides in Sukabumi, One Car is Reported to Have Fallen

Edwin revealed that before the road accident collapsed on the Bocimi Km 64 Toll Road, there was heavy rain for several hours. Rain occurred from 16.00 to 18.00.

"It is suspected that rain caused the road to collapse. "It is estimated that the width of the collapsed road is approximately 5 meters," he said.