PORTALJABAR, BANDUNG CITY - The tornado that hit the Sumedang Regency and Bandung Regency areas, on Wednesday (21/2/2024) at 15:30 WIB caused losses. At least 493 residential units in Kab. Bandung was damaged, and around 10 other units in Kab. Sumedang. Apart from that, there are 422 families affected in the district. Bandung and 412 families in Kab. Sumedang.

Visualization of well-documented tornado events from several angles and positions allows us to see how the tornado phenomenon can have quite a significant impact, especially on the top of buildings, and on other objects that have good pressure vertically, such as billboards and baligo, or other objects such as trees, bus stop roofs and so on.

In fact, some of us thought that this was the first time this incident had occurred in Indonesia because almost complete visual documentation such as the incident in Rancaekek does not always exist.

Head of the National Disaster Management Agency (BNPB) Disaster Data, Information and Communication Center, Abdul Muhari, said that based on data records of extreme weather events, whether tornadoes or strong winds, that BNPB received in 2024, it was quite significant.

"In the 3rd week of January 22-28, extreme weather became the most common disaster in Indonesia, surpassing floods which usually dominate during the rainy season," said Muhari, Friday (23/2/2024).

"Specifically in Java, no less than 14 districts/cities were affected by extreme weather that week. The most significant tornado incident occurred in Sleman District (26/01) which caused 1 MD death, and 71 houses were damaged," he added.

According to Muhari, there are several characteristics of the impact of extreme weather in the form of strong winds or tornadoes that need to be known. The first is damage to the structure of the house, which could be damage to the main structure of the building which could result in the house collapsing, or minor structural damage such as to the roof or upper walls of the house.

"Secondly, outdoor impacts such as fallen trees or billboards which could impact transportation routes (for example blocking roads) or hit other structures," he said.

For house buildings, there are four types of conditions resulting from being affected by strong winds or tornadoes. The first is "uplift" or the lifting of the roof of the house, second is "racking" or the house tilts due to the walls resisting the compressive force of the wind (which can cause the house to collapse), then "sliding" or the position of the house shifts, and finally 'overturning" or the house lifting and turning over. .

Muhari explained that the first structural mitigation effort was through retrofitting or strengthening the structure of the house. The pillars and sides of the house must be connected and tied starting from the roof trusses, the main wall pillars to the foundation.

"This will reduce the potential for the house to be affected by one of the four types of damage that may occur," he said.

Next, look at the relatively flat roofs of houses or warehouse buildings that are quite significantly affected. Strong winds and tornadoes can lift relatively flat roofs more easily than roofs with triangular structures. Likewise, a veranda roof that is directly connected to the roof of the main house will be more easily damaged by a tornado compared to a veranda roof that is structurally separate from the roof of the main house.

Strong winds and tornadoes carry material that can break window glass very easily, therefore having a grille on the inside will protect the occupants of the house if the window glass is broken due to being carried by the wind into the house.

For roofs, especially for warehouses, factories or residential buildings that use tin roofs, using nails with wide, flat heads (some call them thumbtacks) will provide greater resistance to strong winds and tornadoes compared to using ordinary nails.

"Let's always be alert and alert, starting with ourselves and our families. Know the areas that are prone to extreme weather through the InaRisk application and always follow developments in weather forecasts from the competent institutions," said Muhari. (Parno)