Cyclone Seroja

Category 3 Australian region cyclone in 2021

Severe Tropical Cyclone Seroja
Cyclone Seroja approaching Western Australia on 11 April
Meteorological history
Formed3 April 2021
Dissipated12 April 2021
Category 3 severe tropical cyclone
10-minute sustained (Aus)
Highest winds120 km/h (75 mph)
Highest gusts165 km/h (105 mph)
Lowest pressure971 hPa (mbar); 28.67 inHg
Category 1-equivalent tropical cyclone
1-minute sustained (SSHWS/JTWC)
Highest winds140 km/h (85 mph)
Lowest pressure968 hPa (mbar); 28.59 inHg
Overall effects
Fatalities272
Damage>$491 million (2021 USD)
Areas affectedIndonesia, East Timor, Western Australia
IBTrACSEdit this at Wikidata

Part of the 2020–21 Australian region cyclone season

Severe Tropical Cyclone Seroja was the third-deadliest tropical cyclone on record in the Australian region, behind Cyclone Mahina in 1899 and the Flores cyclone in 1973. Seroja brought historic flooding and landslides to portions of southern Indonesia and East Timor and later went on to make landfall in Western Australia's Mid West region, becoming the first to do so since Cyclone Elaine in 1999. The twenty-second tropical low, seventh tropical cyclone, and third severe tropical cyclone of the 2020–21 Australian region cyclone season, the precursor of Seroja formed off the south coast of Timor island as Tropical Low 22U at 18:00 UTC on 3 April 2021; its genesis was related to convectively coupled equatorial waves.[1] The tropical low moved very slowly near the island, while the system's thunderstorms increased in organization. The low intensified into Tropical Cyclone Seroja by 4 April, while it was passing north of Rote Island, while continuing its slow strengthening trend.

Due to the presence of Tropical Cyclone Odette in Seroja's vicinity, interaction was anticipated as the storm moved away from Indonesia and East Timor. Its intensity fluctuated as it moved southwest, with its strengthening being highly hindered due to interaction with Odette. This caused the system to weaken as Seroja moved closer to it, due to a phenomenon known as the Fujiwhara effect. Eventually, Seroja began to restrengthen and weaken Odette, with Seroja absorbing Odette into its circulation on 10 April. Due to Odette, Seroja was steered to the southeast towards Australia, before strengthening even further. At around 8 p.m. local time on 11 April, Seroja made landfall on the western coastline of Western Australia as a Category 3 severe tropical cyclone, slightly south of the coastal town of Kalbarri, bringing heavy rain and hurricane-force wind gusts (about 170 km/h, or 110 mph). Later that day, Seroja began accelerating southeastward while weakening. On 12 April, Seroja emerged off the southern coast of Western Australia while beginning to undergo an extratropical transition, before being absorbed into another larger extratropical cyclone to the south. The name Seroja means lotus in Indonesian.[2]

As of May 2021, it is estimated that at least 272 people were killed by the storm,[3] with 183 people in Indonesia, 42 in East Timor,[4][5][6] and one in Australia.[7][8] At least 72 people from Indonesia and 30 from East Timor are still missing.[9][10] The cyclone damaged or destroyed more than 20,000 houses and five bridges in Indonesia's East Nusa Tenggara province while more than 12,000 people were evacuated to government-owned shelters.[11][12][13] Around 9,000 people were displaced on East Timor, while at least 10,000 homes have been submerged.[14][15][9] Damage reports from Kalbarri, Western Australia started coming in soon after the storm made landfall. The storm is estimated to have caused over $490.7 million (2021 USD) in damages, a majority across Indonesia.[16][17][18][19] The damage caused by Cyclone Seroja in Indonesia was described as catastrophic.[20]

Efforts to relieve the devastating effects of the cyclone came a short time after Seroja left Indonesia. They included almost a million USD in donations, methods to help fight COVID-19, evacuations, local governments sending aid to their respective areas, and more. East Timor also was given outside assistance from other organizations and nations. The Indonesian and Western Australian government's responses were criticized due to the slow nature of their respective responses;[21][22] in the case of Indonesia, this resulted in some high-ranking officials being fired.[23][24]

Meteorological history

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
circle Tropical cyclone
square Subtropical cyclone
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression