Bandung. The Meteorology, Climatology, and Geophysics Agency (BMKG) Station in Bandung clarifies that the intense winds observed in Bandung and Sumedang Regencies in West Java on Wednesday are not categorized as a tornado.

However, the National Research and Innovation Agency (BRIN) insists that the event was a tornado, marking the first such occurrence in Indonesia.

Teguh Rahayu, the Chief of the BMKG Class 1 Geophysics Station in Bandung, explained that the whirlwind phenomena in Bandung, also known as a gustnado, exhibit rotational forces with speeds below 70 kilometers per hour.

"The tornado phenomenon has wind speeds exceeding 70 kilometers per hour. Yesterday evening's incident recorded wind speeds at the Jatinagor Automatic Weather Station (AWS) at 36.8 kilometers per hour," said Teguh in Bandung on Thursday.

On Wednesday, a tornado ravaged hundreds of houses in Nanjung Mekar Village, Rancaekek, Bandung Regency, West Java. The tornado that appeared in Rancaekek manifested as a dark-colored swirling wind. Its sudden appearance caused panic among residents, given the considerable damage to numerous buildings, as seen in various videos where debris was lifted.

According to Teguh, the gustnado was formed due to the development of cumulonimbus clouds, which often lead to extreme weather conditions.

Teguh said gustnadoes are typically short-lived, with durations generally less than 10 minutes. However, not every cumulonimbus cloud development results in gustnado phenomena.

"The development of cumulonimbus clouds often triggers rainfall, and one of its extreme effects is the occurrence of gustnadoes," he explained.

Furthermore, Teguh clarified that tornadoes have greater strength with wind speeds reaching hundreds of kilometers per hour and extensive dimensions, spanning tens of kilometers.

"Tornadoes usually have widespread impacts exceeding 10 kilometers, while the impacts of yesterday's event are estimated to have reached only 3 to 5 kilometers," revealed Teguh.

He urged involved parties to avoid using terms that could cause panic in the community and instead use terms widely understood by the Indonesian public.

Dr Erma Yulihastin, a researcher at the National Research and Innovation Agency (BRIN), insisted that the strong wind observed in Bandung was the first tornado in Indonesia. 

"For the first time, the phenomenon of a small tornado can be detected from satellites," Erma said.

In the same tweet, she explained why she believes the event in Rancaekek was not a gustnado but a tornado, citing satellite photos as evidence.

According to her, gustnadoes or small tornadoes have a micro-scale of 0-2 kilometers. In contrast, tornadoes are on a meso-scale with sizes exceeding 2 kilometers.

"That's why predicting gustnadoes is very difficult because of their micro-scale. It is also challenging to detect them from satellites," she clarified.

Contrarily, the tornado phenomenon with a meso-scale can be detected by satellites. Erma expressed hope to confirm this analysis through wind speed measurements in Rancaekek.