Indonesia: Adverse weather forecast nationwide through at least June 25 /update 2

Event

Thunderstorms, heavy rains, strong winds, and flooding are forecast across much of Indonesia through at least June 25. As of June 22, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued orange (middle level on a three-tier scale) flood warnings across Southeast Sulawesi Province. Yellow thunderstorm, strong wind, flood, and heavy rain warnings are in place across much of Indonesia through June 24. The BMKG has also warned that coastal flooding is possible in many coastal areas of the country through at least June 23 due to dangerous tides associated with the ongoing Super Full Moon phenomenon. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Severe weather events have caused disruptions across many parts of Indonesia in recent days. Authorities in Banggai Regency in Central Sulawesi Province reported one person died after being swept away in floodwaters following heavy rainfall June 19. Nearly 500 homes and 100 people were impacted by the flooding, which also damaged roads, bridges, and health facilities. Flooding and landslides triggered by heavy rainfall in Ambon City in Maluku Province June 19 damaged five homes and affected over 150 people. Over 2,500 people and 500 homes have been affected in parts of Cirebon City in West Java Province due to coastal flooding caused by high tides and exacerbated by heavy rainfall June 13-20. Authorities evacuated 45 people in West Seram regency in Maluku Province due to flooding June 18. The flooding submerged 67 homes and accompanying strong winds caused damage to 15 other houses. Heavy rainfall in Sula Islands Regency in North Maluku Province affected around 300 people and damaged two educational facilities. Landslides blocked roads in Sukabumi Regency in West Java Province June 18. Coastal flooding combined with heavy rainfall affected around 300 people in Mesuji Regency in Lampung Province and flooding in North Buton Regency in Southeast Sulawesi Province affected over 400 people June 18.

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