Cyclone Senyar Kills More Than 600 People in Three Countries, 442 in Indonesia

JAKARTA, KOMPAS - Extreme rainfall of over 400 millimeters per day caused by Cyclone Senyar has triggered disasters of flooding and landslides in three countries. The death toll has reached at least 606 lives, with the highest number of casualties in Indonesia at 442 lives, followed by Thailand with 162 lives, and Malaysia with 2 lives.

The Head of the National Disaster Management Agency (BNPB), Suharyanto, stated that the total number of fatalities from hydrometeorological disasters in Aceh, North Sumatra, and West Sumatra as of Sunday (30/11/2025) has reached 442 individuals. A total of 402 individuals are still reported missing.

Currently, the joint team of BNPB, TNI/Polri, Basarnas, ministries/agencies, and local governments continues to work to expedite search, rescue, logistics operations, and the opening of access to affected areas. "The number of fatalities in North Sumatra is 217, with 209 still missing," said Suharyanto.

The number of fatalities in North Sumatra, particularly in Central Tapanuli, South Tapanuli, the city of Sibolga, North Tapanuli, Humbang Hasundutan, Pakpak Barat, the city of Padang Sidempuan, Deli Serdang, and Nias. The number of missing persons has increased after many reported missing family members to the officers at the evacuation posts.

The refugees are spread across several locations, including 3,600 individuals in North Tapanuli, 1,659 individuals in Central Tapanuli, 4,661 individuals in South Tapanuli, 4,456 individuals in the city of Sibolga, 2,200 individuals in Humbang Hasundutan, and 1,378 individuals in Mandailing Natal.

According to Suharyanyo, land access in several districts in North Sumatra is still cut off due to landslides and damaged bridges. In North Tapanuli, the Tarutung–Sibolga road is blocked at several points, and several villages in Parmonangan and Adiankoting remain inaccessible, affecting a total of more than 12,000 residents.

In Mandailing Natal, the Singkuang–Tabuyung route and the Batang Natal–Muara Batang Gadis segment are cut off at several points, isolating several districts. In Central Tapanuli, the clearing of landslide debris continues on the national roads of Sibolga–Padang Sidempuan, Sibolga–Tarutung, as well as on the damaged bridges at various locations.

Suharyanto stated that in Aceh Province, there have been 96 reported deaths and 75 individuals missing, spread across Bener Meriah, Central Aceh, Pidie Jaya, Bireuen, Southeast Aceh, North Aceh, East Aceh, Lhokseumawe, Gayo Lues, Subulussalam, and Nagan Raya. Meanwhile, the number of refugees has reached 62,000 families in various districts/cities.

Several areas in Aceh remain isolated. A number of main routes are still completely cut off, including the North Sumatra–Aceh Tamiang border, the Meureudu bridge at the Pidie Jaya–Bireuen border, as well as the national road in Gayo Lues, Aceh Tengah, and Bener Meriah. Access from Subulussalam to South Aceh is still inundated without an alternative route.

Meanwhile, the number of fatalities in West Sumatra, according to BNPB data, has reached 129 individuals, with 118 missing and 16 injured. The victims are spread across Agam Regency, Padang Panjang City, Padang City, Padang Pariaman, Tanah Datar, West Pasaman, Pasaman, Solok, Solok City, and South Pesisir. The total number of refugees has reached 11,820 families or 77,918 individuals, with the largest concentration in Padang City and South Pesisir Regency.

According to Suharyanto, several provincial and national roads in West Sumatra are cut off, including the Koto Mambang–Balingka route, Pasar Baru–Alahan Panjang, Panti–Simpang IV, as well as the national roads Padang Panjang–Sicincin and Simpang Taman–Lubuk Sikaping border. Efforts to reopen access are ongoing to ensure that aid distribution can reach all affected areas.

"In general, it is still possible to travel by land," said Suharyanto.

According to data from BMKG, Cyclone Senyar has triggered extreme rainfall in Aceh, North Sumatra, and West Sumatra with an intensity exceeding 300 millimeters (mm) per day. The highest rainfall was recorded in Kuala District, Bireun, with an intensity of 411 mm per day on November 25-26, 2025, as stated by the Head of the Aceh Climatology Station, Muhajir.

According to Muhajir, on that day, there were five regions in Aceh that recorded extreme rainfall exceeding 370 mm. In addition to Kuala District, rainfall of up to 397.4 mm was recorded in Karang Baru District, Aceh Tamiang, 382 mm in Langsa Baro District, Langsa City, 376.6 mm in Pasie Raja District, South Aceh Regency, and 376.6 mm in Meureudu District, Pidie Jaya Regency.

Extreme rainfall exceeding 150 mm has also been recorded in various regions of Aceh, including the northeastern coastal areas of Aceh, the city of Sabang, Aceh Besar, Aceh Singkil, Aceh Selatan, Aceh Tenggara, and the city of Subulussalam.

Neither tropical cyclone seed systems nor tropical cyclones can be effectively managed through weather modification operations (OMC).

Meanwhile, in North Sumatra, a rainfall record was noted at the Cempa Rain Gauge in Langkat Regency, reaching 386 mm per day on November 26-27, as reported by the Head of the North Sumatra Climatology Station, Wahyudin. On that day, extreme rainfall exceeding 300 mm was also recorded in Medan City, Binjai City, Deli Serdang, Batubara, and Humbang Hasundutan.

The Director of Meteorology at BMKG, Andri Ramdhani, stated that in the last five years, several tropical cyclones have been recorded approaching the Indonesian region more frequently. The presence of these cyclones has significant impacts, particularly extreme rainfall, strong winds, and high waves.

"The recent phenomenon of tropical cyclone Senyar is a very unusual occurrence as it formed at a low latitude of about 4.5 degrees North in the Malacca Strait, an area that climatologically should not support the formation of tropical cyclones," he said.

This condition bears similarities to the rare occurrence of Cyclone Vamei in 2001, which also formed in the Malacca Strait at very low latitudes.

A series of atmospheric anomalies such as the strengthening of the Asian monsoon, large convergence in the Strait of Malacca, warm sea temperatures, low wind shear, strengthening of convective activity from regional-scale phenomena such as the MJO, Kelvin and Rossby waves, and the influence of the narrow geography of the strait create conditions for cyclone seeds to develop in areas previously considered safe.

"The changes in weather patterns and the trend of tropical cyclones increasingly approaching Indonesian territory need to be taken seriously, as this indicates that Indonesia is no longer fully protected from the threat of tropical cyclones, whether from the west, north, or south," he said.

According to Andri, in the context of weather modification operation responses, it is important to emphasize that both tropical cyclone seeds and tropical cyclones cannot be effectively managed through weather modification operations (WMO) due to the size and strength of their convective cells, which are very large. "WMO can only be conducted after the cyclone has moved away and is focused on the evacuation stage and post-cyclone recovery to reduce the intensity of residual rain that still has the potential to cause puddles or flooding," he said.

With the increasing tendency of atmospheric anomalies due to climate change, strengthening early detection systems, high-resolution weather modeling, and cross-sector preparedness has become crucial in facing the potential for extreme weather and the impacts of cyclones that may occur more frequently in the future.

In Thailand, it was reported that at least 162 people have died due to Cyclone Senyar, which triggered one of the worst floods in a decade in the country, as stated by the Government of Thailand spokesperson, Siripong Angkasakulkiat, to Reuters on Saturday (29/11/2025).

Approximately 3.5 million people have been affected, and authorities are currently transporting patients and delivering essential supplies, including oxygen tanks, to the inundated communities. Relief measures have been launched by the Thai government, including compensation for households that have lost family members.

However, public criticism of Thailand's flood response is increasing. As reported by AFP, two local officials have been temporarily suspended over allegations of their failure to manage the disaster.

The heaviest rainfall was recorded in Hat Yai City, a major transportation and trade center in Songkhla Province, Thailand, which noted "the heaviest rainfall in 300 years," according to the Royal Irrigation Department. Several locations have recorded rainfall accumulation of nearly 400 millimeters.

Meanwhile, in Malaysia, it was reported that two people have died after floods struck parts of the northern state of Perlis, as reported by the InfoBencana portal from the Department of Social Welfare, Malaysia. More than 34,000 people have been evacuated across Malaysia.

Although the floods in several states such as Melaka have receded, some other states, including Terengganu and Selangor, are still inundated, causing thousands of people to be in temporary relief centers.