Indonesia: Adverse weather forecast nationwide through at least July 10

Event

Thunderstorms, heavy rains, strong winds, and flooding are forecast across much of Indonesia through at least July 10. As of July 10, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued orange (middle level on a three-tier scale) flood warnings across Papua Province. Yellow thunderstorm, strong wind, flood, and heavy rain warnings are in place across much of Indonesia through July 10. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Flooding and landslides triggered by heavy rainfall have recently caused disruptions across many parts of Indonesia. Five villages in Gresik Regency in East Java Province were flooded after the Wotam Dam embankment collapsed following heavy downpours July 6. The flooding affected 447 households and damaged roads and agricultural land in the area. A landslide damaged eight homes in Bogor Regency in West Java Province July 6. Another landslide was reported in Musi Banyuasin Regency in South Sumatra Province late July 5, affecting at least five homes. Authorities in West Seram Regency in Maluku Province reported six fatalities due to flooding and landslides July 5. Landslides heavily damaged a home and blocked a road in the area. Flooding was also reported in parts of Ambon City in Maluku Province July 5, affecting around 180 people. Flooding submerged 76 homes in North Luwu Regency in South Sulawesi Province July 4.

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 regional airports. 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