On 16 December 2021, a tropical depression made landfall on the eastern coast of Peninsular Malaysia, bringing torrential downpours throughout the peninsula for three days. The resulting floods affected eight states across the peninsula, and left at least 54 dead and 2 missing. During its furthest extent, it caused the concurrent displacement of more than 71,000 residents, and have affected over 125,000 people overall.
Declared by government officials as a "once in a century" disaster, it is the worst flood in the country in terms of displaced residents since the 2014–2015 Malaysia floods. It has also been historically compared with the 1971 Kuala Lumpur floods. It is the deadliest tropical cyclone-related disaster to hit Malaysia since Tropical Storm Greg of 1996, which killed 238 people and left 102 more missing.
Record-high precipitations were measured at weather stations at Selangor and Kuala Lumpur. Widespread damages were reported in the states of Selangor and Pahang, especially the district of Hulu Langat and the city of Shah Alam. The Malaysian government has suffered criticism over its delayed response and apathy towards the disaster. Scientists, climate activists, and the media have largely made connections of this disaster as an example of extreme weather attributed to climate change.
Weather events
On 14 December 2021, the Japan Meteorological Agency (JMA) upgraded a westward-moving low-pressure area to a tropical depression. The Joint Typhoon Warning Center (JTWC) began monitoring the system by the next day, noting the presence of a consolidated low-level circulation within the system. The system's chances of developing into a tropical cyclone slowly increased, and on 16 December at 17:30 UTC, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) for the system despite the outflow of Typhoon Rai partially exposing the system's low-level circulation. By 21:00 UTC, the JTWC upgraded the system to a tropical depression, assigning it the designation 29W as it continued over marginally favorable developmental conditions. Shortly after, at 23:00 UTC, the depression made landfall north of the city of Kuantan in the state of Pahang, and began to weaken afterwards, prompting the JTWC to issue its final advisory on the system by the next day. The JMA stopped monitoring the system on 17 December at 12:00 UTC.
Preparations
Prior to the floods, the Kelantan Welfare Department prepared RM1.3 million (US$309,500) for relief efforts. The National Disaster Command Centre (NDCC or NADMA) had planned 5,731 temporary shelters (known locally by its Malay abbreviation, PPS) that could accommodate over 1.6 million victims across the nation for emergency purposes.
On 16 December, the Malaysian Meteorological Department (MMA or MetMalaysia) issued an orange alert for all districts of Kelantan and Terengganu and yellow alerts for Pahang, Perak, Kedah and Penang until 17 December. On the same day, flood warnings were issued by the National Flood Forecasting and Warning Centre (PRABN) to two districts at Kelantan (Kuala Krai District and Jeli District). The NDCC advised on the activation of state- and district-level disaster management committees following the alert. MetMalaysia subsequently issued an amber alert for persisted rainfalls across the Klang Valley. This alert was later raised to a red alert (the maximum level), and was expanded to neighbouring states, including Pahang. The Klang Gates Dam released 25 per cent of its reservoir in stages after water levels exceeded acceptable ranges. By 18 December, flood operation centres were activated in all districts of Kelantan. Later that night, Tuan Ibrahim, the Minister of Environment and Water, released an emergency statement requesting immediate preparations at Kuala Lumpur from floods after the breaching of four main rivers across the city. The SMART Tunnel was activated amidst the increasing precipitation, and achieved record-high diversion volumes of approximately five-million cubic meters of flood water.
Staff and displaced residents of relief centres were regularly screened for COVID-19 to prevent outbreaks from occurring.
Impact
Tropical Depression 29W's crossing of central Malaysia brought long periods of sustained downpours. Several meteorological records were broken during the process. A weather station at Sentul recorded a peak daily rainfall of 363 millimetres (14.3 in), equivalent to a month's worth of rainfall at the region. It was followed by measurements of 273 millimetres (10.7 in) at Sungai Bonus Tun Abdul Razak, 258 millimetres (10.2 in) at Jinjang, and 247 millimetres (9.7 in) at Gombak. Amirudin Shari, the Menteri Besar of Selangor, was notified by the Selangor Department of Irrigation and Drainage that the state had received 380 millimetres (15 in) of rainfall. Previously, the state's highest rainfall measurements were at 180 millimetres (7.1 in).
During its furthest extent, 71,000 people from eight states were evacuated to emergency shelters. The NDCC announced a refined figure of 69,134 people displaced on 21 December. On 23 December, Inspector-General of Police Acryl Sani Abdullah Sani announced the displacement figures at 68,341 people.
Some portions of the Federal Highway, New Klang Valley Expressway (NKVE), and the Karak Highway were exposed to landslides and flooding, which made them entirely impassable. At the Karak Highway, 450 motorists were stranded for two days before they were rescued. 226 people were rescued from the NKVE. The Kemuning-Shah Alam Highway (LKSA), which faced minor flooding, was closed for two days. NDCC estimated that 224 roads (126 state, 98 federal) were disrupted by circumstances related to the floods. 333 electrical substations from six states were closed down for safety reasons, leading to power cuts.
At least 181 COVID-19 cases were detected among evacuees. Health Minister Khairy Jamaluddin warned on 20 December that the disaster could lead to an increase in infections in the country.
Kelantan
Kelantan was among the first states to receive heavy rainfall from Tropical Depression 29W. Five rivers in Kelantan recorded rises in water levels on 16 December, of which three achieved dangerous levels for the next two days. On 17 December, multiple districts of Kelantan were flooded, leading to the evacuation of 548 inhabitants from four districts, housed in eight temporary shelters. Two patients infected with COVID-19 had to be evacuated to Gua Musang Hospital to prevent the spread of infection among other evacuees.
By 18 December, the floods reached Pasir Mas. The first death was reported that day, after the body of a factory operator—who had fallen off a motorcycle while riding through a flooded road—was discovered at 2:22 pm near a Chinese cemetery at Gambang. The number of evacuated victims rose to 1,084, with 17 shelters set up statewide in five districts. Police have been deployed to the Sultan's Pier at Kota Bharu "to prevent crowds from going there to watch the rising river". The displaced victims peaked at 2,632 later that day, but has dropped constantly since then. The figure dropped during the subsequent week to within a thousand people, and by 24 December, the figure was 974 in five different temporary shelters.
The Menteri Besar of Kelantan, Ahmad Yakob, drew comparisons between these floods in his state and the 2014-15 floods, which faced similar issues.
Terengganu
Minor flooding prior to the landfall of 29W on 3 December left 140 people displaced at Setiu and Besut for several days.
On 16 December, when 29W crossed Kelantan, two rivers were reported to have exceeded their respective danger levels (Dungun River and Tebak River). The first temporary shelter was opened at an elementary school at Setiu. It was followed by another temporary shelter at the town hall of Dungun. There were 21 displaced victims. By 18 December, the figure rose slightly to 63, and peaked at 285 by the end of the day. However, as the extent of the floods at the state were minor, only 9 evacuees remained three days later. The last temporary shelter, at Kemaman, was closed on 21 December.
On 30 December, continuous rainfall was again observed in the state. At 4 pm, Dungun became the first to receive flooding, when 69 people were evacuated to a temporary shelter at the district. By late night, the Terengganu state Disaster Management Secretariat was informed that major rivers at Besut, Dungun, and Hulu Terengganu had breached their respective danger levels. By 31 December, the number of evacuees rose to 388. They were housed in two temporary shelters at Dungun.
Selangor and Kuala Lumpur
Selangor and Kuala Lumpur suffered the most rainfall throughout the event. MetMalaysia issued the severest alert for 8 districts at the state for continuous rainfall since 17 December for 4 days. However, floods had already been present at Sepang, Hulu Langat and Klang a day before the warning was issued. 16 rivers had breached the danger level by then. On 18 December, 3,086 victims were displaced in 30 temporary shelters, the majority being at Klang. An extra 11 shelters were set up later that day. 93 water pumps were deployed to remove the floodwaters at the scene, while 134 floodgates were closed to prevent overflows from high tides. Residents of Kajang and Salak Tinggi were advised to evacuate. The main electrical substation at Glenmarie exploded during the night, causing a blackout across some parts of Shah Alam. Two water treatment plants were shut down from the floods, leading to water cuts at 472 areas across Klang Valley. Another plant was forced to limit water outputs due to water quality issues. Water supply trucks could not reach the affected regions as most roads were closed down or cut off from the floods. The Shah Alam City Council (MBSA) published an announcement on the evening refraining people from entering Shah Alam and Klang. At Kuala Lumpur, large tracts of Dataran Merdeka, Jalan Masjid India and Kampung Kasipillay were flooded. Flood waters between the main roads connecting the town of Meru and Bukit Raja were measured with a depth of 2 to 3 metres (6.6 to 9.8 ft). Dozens of residents, who failed to return to their homes in time, were forced to sleep in their cars.
The number of flood victims doubled overnight. On 19 December, 6,242 victims were displaced. In a tweet, the Menteri Besar of Selangor welcomed boat owners to assist in relief efforts, which were coordinated by the state government via the Smart Selangor Operations Centre (SSOC). The severity of the situation has caused the state government to approach the Prime Minister, Ismail Sabri Yaakob, and Minister of Defence, Hishamuddin Hussein, for federal intervention and assistance on the evacuation and humanitarian aid for flood victims. The federal government, although not expecting the situation at Selangor, mobilised federal resources shortly after. Tenaga Nasional, the only electric utility company in Malaysia, announced power disruptions at 82 areas at Klang. The number of displaced victims surpassed 15,000 during the day. The number of temporary shelters meanwhile had increased to 108. The first death at the state was reported the same day, when a body was discovered 350 metres (1,150 ft) way from an apartment at Section 22 of Shah Alam. Videos and images of the discovery went viral across social media networks.
Flood waters began to recede on 20 December. At 4 am, the Selangor State Contingent Police Headquarters announced that 73 roads were closed in the state. The number of displaced victims increased to 32,044 in 162 temporary shelters, the peak figure of the state. Three COVID-19 assessment centres (CAC) in Petaling and Hulu Langat was closed due to the floods. The Kuala Lumpur City Hall (DBKL) had identified at least 40 different locations that were cleared of fallen trees. At 8 am on 21 December, there were 30,632 displaced victims, and by 4.30 pm, the figure had dropped to 26,647. Fifteen people were confirmed to have died from the flood. The death toll rose to 24 the next day. An anonymous source had reported to Free Malaysia Today that members of the Armed Forces had involved themselves in rescue efforts without any orders from the NDCC, and that the Selangor state government were reluctant to call for help from the Armed Forces in rescue operations. The reports have since been denied by the state government.
An apartment in Shah Alam was declared unsafe after concerns over the structural integrity of the complex following the floods. Residents were evacuated to relief shelters in accordance with the local authorities.
Taman Sri Muda (Shah Alam)
The township of Taman Sri Muda, located at Shah Alam, recorded 14 deaths. The township was entirely flooded and suffered catastrophic damage. 16 pumps were used to expedite the pumping process at Sri Muda.