The 2021 Pacific typhoon season was the second consecutive season to have below average tropical cyclone activity, with twenty-two named storms, and was the least active since 2011. Nine became typhoons, and five of those intensified into super typhoons. This low activity was caused by a strong La Niña that had persisted from the previous year. The season's first named storm, Dujuan, developed on February 16, while the last named storm, Rai, dissipated on December 21. The season ran throughout 2021, though most tropical cyclones typically develop between May and October. The season's first typhoon, Surigae, reached typhoon status on April 16. It became the first super typhoon of the year on the next day, also becoming the strongest tropical cyclone in 2021. Surigae was also the most powerful tropical cyclone on record in the Northern Hemisphere for the month of April. Typhoons In-fa and Rai are responsible for more than half of the total damage this season, adding up to a combined total of $2.02 billion.
The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones, which can often result in a cyclone having two names. The Japan Meteorological Agency (JMA) named tropical cyclones that were judged to have 10-minute sustained wind speeds of at least 65 km/h (40 mph) anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigned names to tropical cyclones which moved into or formed as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N and 25°N, regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that were monitored by the United States' Joint Typhoon Warning Center (JTWC) were given a number with a "W" suffix.
Seasonal forecasts
During the year, several national meteorological services and scientific agencies forecast how many tropical cyclones, tropical storms, and typhoons will form during a season and/or how many tropical cyclones will affect a particular country. These agencies included the Tropical Storm Risk (TSR) Consortium of University College London, PAGASA and Taiwan's Central Weather Bureau. The first forecast was released by PAGASA on December 27, 2020, in their monthly seasonal climate outlook predicting the first half of 2021. The PAGASA predicts that only 0–3 tropical cyclones are expected to form or enter the Philippine Area of Responsibility between January and March, while 1–4 tropical cyclones are expected to form between April and June. PAGASA also predicted that the ongoing La Niña could persist until the end of the first quarter of 2021. Tropical Storm Risk (TSR) issued their first extended range forecast on May 11, predicting a slightly below-average season with 24 tropical storms, 15 typhoons and 9 intense typhoons.
On June 23, the PAGASA released their monthly climate outlook for the rest of 2021, predicting 5 to 9 tropical cyclones developing or entering their area of responsibility from July to September, and 5 to 8 tropical cyclones from October to December. TSR issued an update to their forecast on July 7, reiterating their expectations for slightly below-average activity. On August 9, TSR issued their final forecast for the season, slightly lowering their numbers to 25 named storms, 13 typhoons and 7 intense typhoons.
Systems
Tropical Storm Dujuan (Auring)
At 06:00 UTC on February 16, the JMA reported that a tropical depression had formed. Eight hours later, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) for the system. By February 17, the system moved into the Philippine Area of Responsibility (PAR), and was assigned the local name Auring from the PAGASA. At 06:00 UTC on the same day, the JTWC upgraded the system to a tropical depression, giving it the designation 01W. The system was later named Dujuan as the first named storm of 2021. The PAGASA later upgraded Dujuan to a severe tropical storm; however, this only lasted for six hours. On February 20, the storm significantly weakened into a tropical depression due to high vertical wind shear. Both JMA and JTWC issued their final advisories moments after. The storm made landfall over Batag Island in Laoang, Northern Samar at 09:00 PHT (01:00 UTC) on February 22, dissipating thereafter.
Dujuan briefly moved over Palau on February 16 as a tropical depression, bringing heavy rainfall to parts of the country. Classes and government work were suspended on February 22 in parts of Eastern Visayas and Central Visayas, including Surigao del Sur. A total of 242,194 individuals were affected in Northern Mindanao, Caraga, and in the Davao Region. At least 77,811 of the affected individuals were taken to 344 various evacuation shelters in each region. One person was reported dead with four others reported missing, with total damages to agriculture and infrastructure amounting to ₱159.8 million (US$3.29 million).
Typhoon Surigae (Bising)
A low-pressure area south of Woleai developed into a tropical depression on April 12. A few hours later, the JTWC issued a TCFA for the developing storm, with the PAGASA beginning to issue advisories for the tropical depression as it remained outside of the PAR. On April 13, the JTWC upgraded the system to a tropical depression and assigned it the designation 02W. At 18:00 UTC, the JMA upgraded the cyclone to a tropical storm and named it Surigae. On April 15 at 00:00 UTC, the JMA upgraded Surigae to a severe tropical storm as an eye began forming. Later that day, the JTWC upgraded the storm to a typhoon, making it the first of the season. Surigae then entered the PAGASA's Philippine Area of Responsibility, getting the local name Bising. Surigae continued to rapidly intensify until it reached Category 5-equivalent super typhoon status, becoming the most intense typhoon ever recorded in the month of April. Surigae soon reached its peak intensity, with a minimum central pressure of 895 millibars (26.43 inHg), 10-minute maximum sustained winds of 220 km/h (140 mph), and 1-minute sustained winds of 315 km/h (195 mph). A few days later, on April 22, Surigae began to weaken again, with the storm's structure deteriorating and its large eye dissipating. Soon afterward, all of the remaining convection was sheared to the east as the storm moved over cooler waters. Late on April 24, JTWC and JMA declared and issued their final advisory that Surigae had become extratropical.
Winds of up to 30 mph (50 km/h) were recorded in Yap on that day as Surigae passed from the southwest. Damage in Palau was estimated at US$4.8 million. Very strong winds and heavy rains affected the eastern part of the Philippines, with storm surge inundating parts of coastline nearest to the typhoon. Surigae killed a total of 8 people and left another 10 missing. The storm also caused at least ₱272.55 million (US$5.65 million) in damages.
Tropical Depression 03W (Crising)
On May 11, the JTWC noted a persistent area of convection in the Philippine Sea, approximately 184 nmi (341 km) west of Palau. The JTWC issued a TCFA for the convection on May 12, as it further developed in an environment with low vertical wind shear and warm sea surface temperatures. Just three hours later, the agency recognized that the area of convection had quickly consolidated into a tropical depression and assigned it with the identifier of 03W. Around the same time, the JMA had also recognized the storm as a tropical depression while it was to the east of Mindanao. Since the storm developed within the Philippine Area of Responsibility, the PAGASA immediately named the storm Crising once the agency recognized it as a tropical depression as well, and later raised Signal No. 2 warnings for areas in Mindanao. In the early hours of May 13, the JTWC upgraded the system into a tropical storm, with the PAGASA following suit hours later. Later that day, Crising's low-level circulation center became exposed due to wind shear, and it lost organization. At 8:20 p.m. Philippine Standard Time (12:20 UTC), Crising made landfall in Baganga, Davao Oriental as a weakening tropical storm. It quickly degraded as soon as it made landfall, with both the JTWC and the PAGASA downgrading it to a tropical depression at 15:00 UTC. At 03:00 UTC on that day, the PAGASA reported that the system degenerated to an area of low-pressure in the vicinity of Piagapo in Lanao del Sur, thus lifting all warning signals on Mindanao and issuing their final advisory. On May 14, the system dissipated over the Sulu Sea, and both the JMA and the JTWC issued their final advisories on the storm.
In preparations for the storm, the local government of Davao Occidental raised a blue alert on May 13, with the authorities in the area preparing rescue equipment in case of emergency. The PAGASA also warned small vessels near the area to stay away from the rough seas caused by the storm. Schools were ordered to be suspended for that day in Davao Occidental, including the submission of modules. When Crising made landfall, it caused widespread rains and flooding across Mindanao and Southern Visayas. Gusty winds were also felt in parts of Mindanao where the storm passed. In Baganga, some trees were knocked down by strong winds, while strong winds with heavy rainfall were reported in Cateel and Boston, all in the province. Three men and a carabao were required to be rescued from the rising Kabacan River in the early hours of May 14; they were successfully released safely from the said river. An evacuation center in South Upi, Maguindanao were reported to be flooded and some crops near the center were submerged in floodwaters, all due to a rising river near the area. Agricultural damages were estimated at ₱23.2 million (US$486,000).
Tropical Storm Choi-wan (Dante)
On May 27, the JMA and the JTWC noted the persistence of an area of atmospheric convection about 425 nautical miles (787 km; 489 mi) south-southeast of Guam. The area's nearby environment exhibited low wind shear and warm sea surface temperatures, which were ideal conditions for tropical cyclogenesis. The JMA assessed the area to have developed into a tropical depression on May 29 at 06:00 UTC. The PAGASA made a similar assessment in a Tropical Cyclone Advisory issued at 15:00 UTC. The JTWC later followed with their own assessment, identifying the center of the newly developed tropical depression and assigning the designation 04W. As the system tracked westward, it entered the Philippine Area of Responsibility at 01:00 PHT (17:00 UTC). The PAGASA then named the storm Dante in its first Tropical Cyclone Bulletin for the storm. Dante further organized in the Philippine Sea, and on May 30 at 15:00 UTC, the JTWC upgraded it to a tropical storm, with the PAGASA doing the same at 21:00 UTC. On the next day at 00:00 UTC, the JMA also upgraded Dante into a tropical storm, giving it the international name Choi-wan. Choi-wan's center was exposed due to a tropical upper tropospheric trough from the northeast, inducing shear on the system. On June 1 at 12:30 UTC, Choi-wan made landfall on Sulat, Eastern Samar as a minimal tropical storm, with the JTWC downgrading it to a tropical depression at 15:00 UTC. It made a second landfall on Cataingan at 17:00 UTC. Choi-wan made several more landfalls on the Philippines, making its third landfall on Balud, Masbate at 19:30 UTC. It made a fourth landfall on Romblon, Romblon on June 2 at 00:00 UTC, a fifth on San Agustin, Romblon at 00:50 UTC, a sixth on Pola, Oriental Mindoro at 06:00 UTC, a seventh on Tingloy, Batangas at 11:20 UTC, and an eighth and final landfall on the Calatagan Peninsula before moving into the South China Sea. On June 3 at 03:00 UTC, the JTWC upgraded Choi-wan back to a tropical storm. At 03:00 UTC, the PAGASA removed all Tropical Cyclone Warning Signals as Choi-wan moved away from the country. Choi-wan then exited the PAR on June 3 at 18:00 UTC before weakening into a tropical depression on the next day at 06:00 UTC and re-entering the PAR at 08:00 UTC. Then, it passed southeast of the island of Taiwan before moving out near the Okinawa Prefecture and heading towards Japan. On June 5 at 06:00 UTC, the Japan Meteorological Agency issued their final advisory on the system. 3 hours later at 09:00 UTC, the JTWC upgraded Choi-wan back into a tropical storm, however at 15:00 UTC, the Joint Typhoon Warning Center downgraded the system to a tropical depression, also issuing their final advisory on the system.
Heavy rains caused floods in parts of Mindanao; 11 fatalities were reported, 3 people were injured, and 2 people are missing. As of June 4, 55,226 people were affected and 16,680 people are inside evacuation centers. A total of ₱307.2 million (US$6.39 million) of damages were incurred throughout the country, of which ₱152.1 million (US$3.17 million) was agricultural damages and ₱155.1 million (US$3.23 million) was related to infrastructure. On June 1, classes and government work for parts of Davao de Oro, Eastern Samar, Leyte, and Surigao del Sur were suspended for the day.