Indonesia: Adverse weather forecast nationwide. Flooding ongoing as of May 24

Event

Thunderstorms and heavy rains are forecast across much of Indonesia, while flooding is ongoing in Kalimantan as well as North Sumatra and West Java provinces. As of May 24, the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) has issued a yellow heavy rain, thunderstorm, and flood warnings (the second-lowest level on a four-tier scale) for most of Indonesia. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Disruptions are ongoing in several regions of the country due to adverse weather in recent days. Reports indicate that at least four people have died and five others were left homeless in Cipelang Village, Cijeruk District, Bogor Regency, West Java Province, due to a landslide May 21. Floods have damaged around 2,500 homes and affected around 12,000 residents in Kendal and Pemalang Regencies in Central Java Province.

Flooding in Medan City, North Sumatra Province May 20 damaged more than 11,000 homes and affected around 45,000 people, while a tornado May 22 injured two people. Heavy rain caused the Barito River to overflow, damaging homes and affecting more than 2,000 people in North Barito Regency, Central Kalimantan Province. Reports indicate that flooding has damaged 977 houses in Murung Raya Regency, Central Kalimantan Province May 20 and affected almost 3,000 people across 11 villages in North Malinau District, Malinau Regency, North Kalimantan Province.

Hazardous Conditions
The storms could produce rounds of heavy rainfall, strong winds, and isolated thunderstorm activity across Indonesia. Sustained heavy rainfall could trigger further flooding in low-lying communities near rivers, streams, and creeks. 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 some delays and cancellations at airports in the region. 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 that see heavy rainfall and potential 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