JAKARTA -- The death toll from heavy storms across three Indonesian provinces on Sumatra has jumped to more than 400 with a similar number still missing and 290,000 people evacuated as the impact of extreme weather across Southeast Asia over the past week continues to grow.
Southern Thailand, northern Malaysia and Vietnam have also been badly affected by the deluges that are being widely attributed to climate change. The combined number of fatalities is more than 700.
"North Sumatra is the most affected, with heavy rains falling since November 25 due to Cyclone Senyar and Cyclone Koto, both rare natural phenomena in the Sumatra region," said Suhariyanto, head of Indonesia's National Disaster Mitigation Agency (BNPB), on Saturday evening.
Two other provinces, West Sumatra and Aceh, also experienced heavy rainfall on Friday, he added. BNPB on Sunday evening updated the confirmed death toll across the affected area to 442 with 402 missing. Some 1.1 million people have been affected and 290,000 forced to evacuate their homes.
Evacuations and the distribution of aid have been hampered by landslides blocking access routes in highland areas.
"There are still points that cannot be reached, and there are indications that casualties remain in those locations," Suhariyanto said, adding that prolonged power cuts and disrupted communication networks were also hampering rescuers and relief teams.
"To mitigate this, we have dispatched electric generators and Starlink units to local governments, evacuation centers, as well as to the military and policemen," he said.
Evacuation operations in the three provinces are being led by BNPB, the National Search and Rescue Agency, the military, and the police.
"Weather conditions and soil structure remain unstable, and this presents a major challenge," said Hery Marantika, Head of the Search and Rescue Office in Medan, North Sumatra.
Last Wednesday, the Meteorology, Climatology, and Geophysics Agency (BMKG) warned of the potential impact of tropical cyclones Senyar and Koto on the three affected provinces, as well as Riau and the Riau Islands.
"Over the past 10 years, tropical cyclones have become more frequent, following a pattern from November to March or April of the following year," said BMKG Chairwoman Dwikorita Karnawati.
She linked the increasing frequency of cyclones to climate change, noting that Indonesia's extensive vulnerable zones, particularly its hills and highlands, tend to suffer first from hydrometeorological disasters.
Rianda Purba, executive director of the Indonesian Forum for the Environment (Walhi) in North Sumatra, said Central Tapanuli, the province's worst-hit regency, lies along the slopes of the Bukit Barisan mountain ridge on Sumatra.
"Land cover in the upstream and riverbank areas of this region has significantly declined, mainly due to deforestation for the Batang Toru hydropower project, local logging activities, and gold mining," he told Nikkei Asia.
Despite the storms affecting three provinces with a combined population of more than 20 million, the central government has not declared a national disaster. Emergency status has instead been determined by each provincial or regency-level government.
"Indonesia has only declared national disaster status for the COVID-19 pandemic and the 2004 tsunami. ... [The considerations] were the scale of the victims and the difficulty of access, which were mitigated and evacuated quickly," said Suhariyanto.
Analysts are also warning about the availability of mitigation funding, as the three institutions responsible for disaster monitoring and response -- BNPB, BMKG, and the National Search and Rescue Agency -- had their budgets earlier this year in provide additional funding to President Prabowo Subianto's flagship projects.
Observers are most concerned about the cuts to BMKG, as these affect the country's monitoring capacity and early-warning systems.
On Friday, Prabowo said the government had acted swiftly, deploying aid by land and air.
"The conditions are very difficult, with many roads blocked, and the weather remains unfavorable, making it hard for our helicopters and planes to land," he said.
The central government has sent three Hercules C-130 aircraft and one A-400 aircraft carrying emergency supplies for affected residents.
