Indonesia: Adverse weather forecast across much of the country through at least Feb. 3 /update 1

Event

Thunderstorms, heavy rains, strong winds, and flooding are forecast across much of Indonesia through at least Feb. 3. As of Jan. 31, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued orange (middle-level on a three-tier scale) flood warnings across West Kalimantan Province Jan. 31-Feb. 2, as well as for South Sulawesi Province Jan. 31, East Java Province Feb. 1-2, and West Nusa Tenggara Feb. 2. Yellow thunderstorm, strong wind, and heavy rain warnings have been issued across much of Indonesia Jan. 31-Feb. 2. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Heavy rainfall over recent days has resulted in severe flooding and associated disruptions across many parts of the country. Manado City in North Sulawesi Province was among the worst-affected areas, where heavy rainfall late Jan. 27 triggered flooding and landslides. Authorities have reported at least five weather-related fatalities in the city. The floods and landslides have damaged more than 1,000 houses, and around 1,600 people have been displaced. The Manado City Government has declared a state of emergency through Feb. 2. Tens of thousands of people have also been affected by flooding across Aceh Province in recent weeks, including more than 7,000 people impacted by heavy downpours in Pidie Regency Jan. 28-30. More than 1,300 people in the regency have been displaced, and hundreds of homes have been submerged by floodwaters. Hundreds of homes have also been inundated due to flooding in Sambas Regency in West Kalimantan Province since Jan. 28.

Hazardous Conditions
Further sustained heavy rainfall could trigger additional, 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 National Board for Disaster Management