Indonesia: Adverse weather forecast across much of the country through at least Oct. 10 /update 2

Event

Thunderstorms, heavy rains, strong winds, and possible flooding are forecast across much of Indonesia through at least Oct. 10. As of Oct. 7, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued orange (middle-level on a three-tier scale) flood warnings for Aceh, West Kalimantan, and West Java provinces and the Jakarta metropolitan area through Oct. 8. Yellow thunderstorm, strong wind, and heavy rain warnings have been issued across much of the rest of Indonesia. The heavy rainfall is likely to persist through at least Oct. 10. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Heavy rainfall late Oct. 4 triggered flooding in parts of the Jakarta metropolitan area due to overflowing rivers. The flooding submerged a number of homes in parts of South, Central, West, and East Jakarta, and at least six roads in the region were inundated by floodwaters. Additional heavy rainfall Oct. 6 collapsed a wall in Cilandak District, South Jakarta, killing three people and injuring two others. 17 roads in South Jakarta are flooded while at least 270 people had evacuated to the Al Mustaghfirin Mosque in Kalibata Village.

Floodwaters are affecting parts of Bandar Pusaka, Kejuruan Muda, Kota Kuala Simpang, and Sekrak districts. Heavy rainfall, together with the Krueng Keureuto, Krueng Peutoe, Pirak, Nisam, Sawang, and Krueng Pase rivers overflowing, has forced the evacuation of more than 35,600 people across 12 districts in North Aceh Regency. The worst affected is Lhoksukon District. Initial assessments indicate that more than 6,700 houses have been damaged. The Aceh government has declared a disaster emergency status.

Hazardous Conditions
Sustained heavy rainfall could trigger further flooding in low-lying communities near rivers, streams, and creeks. Coastal flooding is also possible during high tides. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil. Power outages could occur throughout the affected area.

Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could also cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

The disruptive weather may cause delays and cancellations at airports across the affected area. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Seek updated information on weather and related disruptions, including road conditions, before driving or routing shipments through areas where severe weather is forecast. Plan accordingly for potential freight delivery delays if routing shipments by truck through the affected area. Do not attempt to drive through flooded areas. Charge battery-powered devices if prolonged electricity outages occur.

Resources

Indonesian Agency for Meteorology, Climatology, and Geophysics
Indonesian Agency for Meteorology, Climatology, and Geophysics (Twitter)
Indonesian National Board for Disaster Management