2021 Pacific typhoon season

Season overview

The La Niña that had developed in 2020 carried into 2021, and the Philippine weather agency PAGASA expected it to last at least through the first quarter. Tropical Storm Risk forecast a slightly below-average season in May, with 24 tropical storms, 15 typhoons and 9 intense typhoons, and by August it had trimmed its outlook to 13 typhoons, 7 intense typhoons and an accumulated cyclone energy (ACE) of 230, against a 1965 to 2020 average of 294.

The season fell short even of that reduced outlook. On the site's measure it generated an ACE of 209, and it was the second below-average season in a row in the basin. Storms were tracked from mid-February, when Tropical Storm Dujuan formed, until Typhoon Rai faded on 20 December, but only 10 of the 24 tropical storms reached typhoon strength, and a small group of intense typhoons produced much of the year's energy.

How the season unfolded

Tropical Storm Dujuan opened the season in February, drifting past Palau and weakening in strong wind shear before coming ashore on Northern Samar as a depression. Typhoon Surigae formed south of Woleai in mid-April and became the first typhoon of the year on 15 April, peaking two days later east of the Philippines. May and June brought only weak systems: a small storm known in the Philippines as Crising struck Davao Oriental, Tropical Storm Choi-wan crossed the Philippines in a string of landfalls, and Tropical Storm Koguma moved ashore in northern Vietnam. Typhoon Champi, the second typhoon, passed near Guam and the Bonin Islands in late June before turning away toward Japan.

Activity picked up in the second half of July. Typhoon In-fa and Typhoon Cempaka formed within two days of each other, with Cempaka moving into southern China and In-fa slowly tracking toward Zhejiang. Tropical Storm Nepartak, a system with subtropical features, followed and swept up to northern Japan. At the turn of July and August the western Pacific produced a burst of depressions in about a week; most were short-lived, but Tropical Storm Lupit, Tropical Storm Mirinae and Tropical Storm Nida formed from the cluster. The rest of August was comparatively quiet.

September brought the season's second peak. Typhoon Conson and Typhoon Chanthu formed on the same day east of the Philippines, and Chanthu grew into a Category 5 storm within a few days. After a short pause Typhoon Mindulle and Tropical Storm Dianmu formed on 22 September, Mindulle over the open Pacific and Dianmu in the South China Sea, where it quickly reached Vietnam.

October produced Tropical Storm Lionrock, Tropical Storm Kompasu, Tropical Storm Namtheun and Typhoon Malou, along with a short-lived storm that struck southern Vietnam near Nha Trang. Malou peaked at Category 2 strength near the Bonin Islands. After an unusual four-week gap, Typhoon Nyatoh formed at the end of November and briefly became the season's fifth major typhoon far from land, and Typhoon Rai closed the season in mid-December with a destructive crossing of the Philippines and a second Category 5 peak in the South China Sea.

Strongest storms

Typhoon Surigae was the strongest storm of the year. It intensified rapidly over the Philippine Sea and reached a peak one-minute wind of 170 knots and a minimum pressure of 882 hPa on 17 April, making it the most intense typhoon recorded in April anywhere in the Northern Hemisphere. The JMA, which uses ten-minute winds, put its peak at 120 knots and 895 hPa. Surigae stayed offshore, curving northeast east of the Philippines before becoming extratropical on 24 April, and it was also the longest-lived storm of the season.

Three more storms reached Category 5. Typhoon Chanthu, a compact storm with a pinhole eye, peaked at 155 knots and 902 hPa on 10 September after a second round of intensification, shortly before crossing Batanes in the far northern Philippines. Typhoon Mindulle reached 140 knots and 916 hPa on 26 September over open water, then went through an eyewall replacement and weakened in dry air before becoming extratropical off Hokkaido. Typhoon Rai peaked at 150 knots and 908 hPa on 16 December, just before its first Philippine landfall.

Typhoon Nyatoh was the fifth major typhoon, reaching 130 knots and 928 hPa on 2 December when a jet interaction drove sudden rapid intensification; strong shear, dry air and cooler water then tore it apart within hours. Typhoon In-fa peaked at 95 knots in July, one knot short of major-typhoon strength on the site's measure.

Landfalls and impacts

Typhoon Rai was the season's most destructive storm. It struck General Luna, Surigao del Norte, on 16 December as a Category 4 equivalent storm with one-minute winds near 155 mph, then made a string of further landfalls across Dinagat, Southern Leyte, Bohol, Cebu, Negros Oriental and finally Palawan. By 6 January 2022, 410 deaths had been reported, 111 of them in Bohol, and the Wikipedia season table lists damage of about US$968 million in 2021 dollars.

Typhoon In-fa was the costliest storm of the season, with damage listed at about US$2.04 billion in 2021 dollars and 6 deaths. It made landfall on Putuo Island off Zhejiang, near Shanghai, on 25 July, and moisture from In-fa and Typhoon Cempaka fed the heavy rain behind the devastating floods in Henan. Cempaka itself came ashore in Yangjiang, Guangdong, and later drifted across the border into northern Vietnam.

Two autumn storms hit the Philippines hard. Typhoon Conson intensified rapidly just before reaching Eastern Samar on 6 September and made nine landfalls across the central islands; the national disaster council counted 23 deaths and ₱5.17 billion (US$88.3 million) in infrastructure and agricultural damage, and flooding killed 2 more people in Vietnam. Tropical Storm Kompasu, a broad monsoon storm, crossed far northern Luzon on 11 October and then struck Hainan; by 31 October the disaster council had confirmed 43 deaths in the Philippines, with 16 people missing and damage of ₱6.39 billion (US$126.5 million), and one person died in Hong Kong.

Weaker storms also took lives. Tropical Storm Choi-wan killed 11 people in the Philippines in early June, Tropical Storm Lupit left 4 dead in Taiwan in August, and Tropical Storm Dianmu was blamed for 8 deaths in Thailand and Vietnam in late September. Typhoon Chanthu scored a direct hit on Batanes, where residents called it the fiercest storm they had seen, and then briefly shut the ports of Shanghai and Ningbo-Zhoushan. Tropical Storm Nepartak became the first tropical cyclone to make landfall in Miyagi Prefecture since reliable records began in 1951, forcing Olympic rowing events in Tokyo to be rescheduled. In mid-December a short-lived depression came ashore near Kuantan, and its remnant rains contributed to the worst flooding in central Malaysia since 2014.

Counts, names and warning changes

Agency counts differ from the site's because they measure different things. The JMA, which names storms for the basin, counted 22 tropical storms and 9 typhoons using ten-minute winds, making 2021 its least active season since 2011. The JTWC counted 26 tropical storms and 10 typhoons from its own one-minute warnings, and PAGASA named 15 systems that formed in or entered its area of responsibility. The site counts 24 tropical storms from US-agency one-minute winds in the IBTrACS archive, so short-lived systems such as Crising, which the JTWC rated as a tropical storm but the JMA kept as a depression, appear in the site's count without an international name.

Four international names made their debut in 2021: Surigae, Koguma, Cempaka and Nyatoh, replacing names retired after the 2015 and 2016 seasons. After the season PAGASA retired Jolina, Maring and Odette, its local names for Conson, Kompasu and Rai, and in 2023 the Typhoon Committee retired Conson, Kompasu and Rai themselves. Rai also helped prompt PAGASA to revise its tropical cyclone wind signals and intensity scale in March 2022, under which Rai was classed as a super typhoon.