Two people have died following a landslide at the Banjaran Hot Spring near the town of Tambun, in Perak State, Malaysia, on Tuesday 10 November 2020. The pair, described as a man and a woman in their thirties, were staying at one of four tourist units located around the springs, when the landslide occurred, at about 1.00 am local time. Other guests were evacuated from the site immediately, and the emergency services contacted when the missing couple could not be found. Their bodies were eventually located at about 10.00 am. The emergency services reported difficulty extracting the bodies due to ongoing Earth movements at the site.
The incident happened after several days of heavy rain, in the area, associated with the onset of the Northwest Monsoon. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. In this case the area where the landslides occurred is reported to be located amid soft limestone hills, covered by thin soil and trees, which are thought to have been weakened by the excessive rainfall.
Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season, the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.
Malaysia has become increasingly landslip-prone in recent years due to extensive deforestation, which leaves soil exposed to heavy tropical rainfall. Concerns have also been raised about the large number of construction sites on steep hillslopes in urban areas, where workers are particularly vulnerable to landslip events during the Monsoon Seasons.
There are at least sixty hot springs on the western part of the Malay Peninsula, which have fuelled the development of a range of tourist developments. The water from these springs lacks the high sulphur content of some geothermal systems, making them attractive for such developments, although concerns have been raised about the levels of sodium and fluorine in the water, leading some experts to conclude that the water should not be drunk without treatment.
The springs are thought to be fed by rainwater percolating through faults in granite batholiths beneath the Malay Peninsula, then entering aquifers in sedimentary rocks. Because the water that has passed through the batholith has been heated considerably, it floats above water from other sources, rapidly rising to the surface at any available outlet, and thereby creating numerous hot springs in the region.
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