Causes Of Sumatra Flash Floods: Starting From Rainfall To Environmental Damage

The cause of the Sumatran flash flood. (Between)

YOGYAKARTA - The Ministry of Energy and Mineral Resources (ESDM) expressed deep condolences for the floods and landslides that hit a number of areas in Sumatra due to extreme weather that occurred in the last few days. At this time, the government prioritizes handling affected residents and regional recovery. What do you think is the cause of this Sumatran flash flood?

Mereology expert and lecturer from the Atmospheric Science Expert Group, Bandung Institute of Technology (ITB), Dr Muhammad Rais Abdillah S Si, M Sc, explained that the first cause of the major disaster occurred, namely high rainfall. As is known, Sumatra is at the peak of the rainy season.

"Indeed, the Tapanuli region is in the rainy season, because northern Sumatra has a rainy pattern throughout the year or two peaks of rain in one year, and is currently at its peak," he said as quoted by the ITB website.

Based on records from the Meteorology, Climatology and Geophysics Agency (BMKG), the island's rainfall reaches 150-300 millimeters. Thus, the recent rain in Sumatra is included in the extreme category.

According to Rais' observation, the vorticity or cyclonic circulation that occurred around northern Sumatra also exacerbated rainfall. This phenomenon then developed into a Tropical Senyar Cyclone system, which occurred around the Malacca Strait and headed west.

"On November 24, there was already a rotating system from the Malaysian Peninsula. In meteorology, we refer to it as vortex, although at that time it was still in the form of seeds and his eyes were not clearly visible," he explained.

Rais explained that the cyclone was not as strong as generally in the Pacific Ocean or the Indies. However, it still forms rain clouds.

Furthermore, the phenomenon of meso and synoptic scale atmospheres also has an effect. For example, vortex, which is strong winds from the north that carry moist air masses and strengthen the formation of rain clouds.

In addition to rainfall, flash floods looked very severe because they were accompanied by a decrease in the capacity of the region. This was revealed by the Lecturer of the ITB Geodesic and Geomatic Engineering Study Program, Dr. Heri Andreas ST MT.

"When the precipitation drops, some of the water seeps into the ground (infiltration), while the rest flows on the surface as (runoffs). The proportion between the two depends heavily on land cover and soil characteristics," explained Heri.

He argues that the conversion of forest area functions into plantations and settlements reduces the water absorption capacity in the area. So Heri emphasized that the urgency of risk-based spatial planning, water-retaining area conservation, and geospatial modeling are very important for long-term mitigation needs.

"When the natural water-retaining area disappears, the area loses its ability to withstand runoff. As a result, the rain that falls directly flows into the river and triggers flooding," he explained.

In addition to spatial planning, Rais also explained that accurate and scientific weather early warnings must also be carried out. The impact of disasters can also be minimized when coupled with increased disaster literacy and public education.

That's a review of the causes of the Sumatra flash flood that has been happening lately. Visit VOI.id to get other interesting information.