Indonesia: Adverse weather forecast across much of the country through at least Oct. 15 /update 4

Event

Thunderstorms, heavy rains, strong winds, and possible flooding are forecast across much of Indonesia through at least Oct. 15. As of Oct. 12, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued orange (middle-level on a three-tier scale) flood and heavy rainfall warnings for East, Central, and West Java and Lampung provinces Oct. 12-13 and the Jakarta Metropolitan Area Oct. 13. Yellow thunderstorm, strong wind, and heavy rain warnings have been issued across much of the rest of Indonesia Oct. 12-14. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Flooding is affecting several parts of Jakarta as of Oct. 12 after heavy rainfall Oct. 11 caused the Ciliwung River to overflow. Dozens of neighborhoods have been affected by flooding, with East and South Jakarta being the worst affected areas. Classes have been suspended at some schools in Sintang Regency in West Kalimantan Province as of Oct. 12 due to flooding. The flooding triggered by heavy rainfall since Oct. 11 has affected more than 43,000 people and a number of roads in the area have been made impassable by floodwaters. Hundreds of people in Mamuju Regency in West Sulawesi Province were evacuated due to flash flooding Oct. 11. The flooding cut-off parts of Kalukku subdistricts leading to the evacuation of 154 people to emergency shelters. Authorities reported one fatality and three other people were injured after heavy rainfall triggered a landslide in Bogor City in West Java Province Oct. 11.

Flooding in North Aceh Regency, Aceh Province, triggered by heavy rainfall since Oct. 4 has led to the evacuation of nearly 40,000 people as of Oct. 10. Over 50,000 people have been affected by the flooding that has also damaged at least 17 roads and bridges and 5 homes. Heavy rainfall in East Aceh Regency Oct. 7 also inundated around 1,000 homes and led to more than 300 people being evacuated. Authorities in Kebumen Regency in Central Java Province reported one fatality after floods and landslides impacted the region Oct. 7. More than 1,250 people have been affected by flooding and more than 200 people by landslides in the regency.

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