Anticipating Drought and Forest Fires, BMKG-BNPB Conduct Weather Modification
The Meteorology, Climatology and Geophysics Agency (BMKG), together with the Nusantara Capital City Authority (OIKN), the Indonesian Air Force (TNI-AU), the National Disaster Management Agency (BNPB) and the East Kalimantan provincial government, is carrying out weather modification operations (OMC) to address the water deficit in the Sepaku Reservoir and forest and land fires (karhutla).
BMKG Director of Weather Modification Operations, Budi Harsoyo, said that smoke from forest and land fires generally moves from the northwest to the northeast, crossing administrative boundaries into North Kalimantan and Sabah, Malaysia. Meanwhile, data as of 20 August 2026 shows that East Kalimantan generally experienced very short to long categories of days without rain, with the longest duration recorded in West Kutai and Paser regencies, which had 28 consecutive days without rain.
“Weather modification does not create rain, but optimises the potential of available clouds. If cloud conditions are supportive, cloud seeding is carried out to accelerate the process of rainfall and expand its area,” Budi explained in a press release.
Based on data from the Nusantara Capital City Authority, water reserves in the Sepaku Reservoir, which is the raw water source for the IKN area, have continued to decline since July due to the impact of El Niño. Meanwhile, BMKG monitoring shows that the number of hotspots in East Kalimantan from 1 to 23 August 2026 reached 13,273 points, an increase of 35.5 percent compared to the same period in 2015, when the peak of the dry season coincided with El Niño.
BMKG monitored the potential for cloud growth in East Kalimantan from 23 to 31 August as high to moderate, especially in the northern part of the province. However, there was a decline in cloud growth potential from 28 to 31 August, resulting in relatively dry weather across most of East Kalimantan.
Furthermore, there was potential for light to moderate rain in western, northwestern and northern East Kalimantan on 24-26 August. From 27 August to 1 September, the potential intensity and distribution of rain decreased significantly across most of the province.
In carrying out the OMC, BMKG considered not only the number of detected hotspots but also the potential for rain in the target areas. Accordingly, OMC was carried out in IKN from 22 to 27 August to address the decline in Sepaku Reservoir water levels. The results were visible with rain falling in the area and its surroundings over the past two days until this morning.
“Then, OMC in Berau Regency began on 24-28 August to address hotspots based on a request from the Berau Regent to BNPB and BMKG,” Budi added.
Meanwhile, East Kalimantan Deputy Governor Seno Aji explained that the regional government has prepared additional measures to control the threat of drought and forest fires that could still occur until the end of August 2026. Currently, around 200 hotspots are monitored in East Kalimantan. Along with the implementation of OMC, a joint team consisting of the TNI, Polri, BPBD, district and city governments, and Fire Care Communities continues to be deployed to tackle emerging hotspots.
Currently, the status of forest and land fire handling in East Kalimantan remains at Disaster Alert level, and has not yet been raised to Emergency Alert. However, Seno reminded each region to be aware of vulnerability and disaster conditions in their areas so that they can immediately request assistance from BNPB if they meet the criteria for emergency alert.
On the other hand, BMKG and stakeholders have established OMC command posts at several locations to support water, food and safety resilience. The Pekanbaru post in Riau has flown 26 sorties of seeding material for forest and land fire handling from 30 July to 29 August.
The Palembang post in South Sumatra has carried out OMC for forest and land fire handling on 22-26 August. Meanwhile, the Pontianak post in West Kalimantan has carried out OMC from 23 to 27 August.
In addition to handling forest and land fires and reservoir replenishment, OMC was also carried out by BMKG and the DKI Jakarta provincial government on 22-26 August to improve air quality in Jakarta.