[12] The flood is thought to have been caused by high rainfall intensity, which triggered river overflows that began on January 9, 2021.

[13] However, the Director of Indonesian Forum for Environment for South Kalimantan, Dwi Cahyono, argued that the flood was caused by environmental degradation in the form of hundreds of mining holes that were not reclaimed and nearly fifty percent of the 3.7 million hectares of land were controlled by mining and oil palm companies.

President Joko Widodo posted on social media that Indonesia currently struggles against two natural disasters; 2021 Sumedang landslides and 2021 West Sulawesi earthquake, but did not mention the floods.

Consequently, hashtag "#KalselJugaIndonesia" (South Kalimantan is also Indonesia) trended on Twitter as protest of government's lack of coverage.

[18][19][20] Later president post a video on the disaster that he already received direct report from South Kalimantan governor, Sahbirin Noor and urged all government personnel to provide aids necessary for the victims especially inflatable boat.