 Surigae nearing its peak intensity east of thePhilippines on April 17 | |
| Meteorological history | |
|---|---|
| Formed | April 12, 2021 |
| Extratropical | April 24, 2021 |
| Dissipated | April 30, 2021 |
| Violent typhoon | |
| 10-minute sustained (JMA) | |
| Highest winds | 220 km/h (140 mph) |
| Lowest pressure | 895hPa (mbar); 26.43 inHg |
| Category 5-equivalent super typhoon | |
| 1-minute sustained (SSHWS/JTWC) | |
| Highest winds | 315 km/h (195 mph) |
| Lowest pressure | 882hPa (mbar); 26.05 inHg |
| Overall effects | |
| Fatalities | 9 total |
| Damage | $10.5 million (2021USD) |
| Areas affected | Caroline Islands,Sulawesi,Philippines,Taiwan |
IBTrACS | |
Part of the2021 Pacific typhoon season | |
Typhoon Surigae, known in the Philippines asSuper Typhoon Bising, was the strongest Northern Hemispheretropical cyclone to form in the first four months of the calendar year.[1]: S247 [2][3] The second named storm, firsttyphoon and firstsuper typhoon of the2021 Pacific typhoon season, Surigae was the strongest tropical cycloneworldwide in 2021. "Surigae" is a North Korean word for theblack-eared kite.
The storm originated from a low-pressure area south of theMicronesian island ofWoleai. The low organized into a tropical depression on April 12. At 18:00 UTC that day, it strengthened into a tropical storm and wasnamedSurigae by theJapan Meteorological Agency (JMA). Very favorable environmental conditions then allowed Surigae to begin a bout ofrapid intensification after becoming a typhoon on April 15; by April 17, the storm reached its peak intensity with 10-minute sustained winds of 220 km/h (140 mph),[nb 1] 1-minute sustained winds of 315 km/h (195 mph), and a minimum pressure of 895 hPa (26.4 inHg). Afterward, weakening outflow and aneyewall replacement cycle caused Surigae to gradually weaken as its track shifted north-northwestward in thePhilippine Sea. Following the eyewall replacement cycle, Surigae became anannular tropical cyclone on April 19, and restrengthened slightly. On April 22, the storm began to rapidly weaken as it accelerated northwestward into unfavorable environmental conditions, transitioning into asubtropical storm the next day. The subtropical system subsequently underwentextratropical transition, which it completed by April 24. Three days later, Surigae's remnant explosively intensified into abomb cyclone near theAleutian Islands, attaining hurricane-force winds. Afterward, the system gradually weakened as it turned eastward, crossing theInternational Date Line on April 30 and fully dissipating that same day.
Upon Surigae's naming,watches and warnings were issued for the island ofYap in theFederated States of Micronesia and the islands ofKoror andKayangel inPalau as well. The typhoon leftUS$4.8 million in damage in Palau after cutting off power and water and destroying infrastructure.[nb 2] Later, warnings were raised for parts of thePhilippines as the typhoon moved closer to the nation, with evacuations taking place in eastern regions of theVisayas. The Philippines was battered with heavy rainfall, flooding and strong winds as Surigae passed just offshore. Landslides displaced over 100,000 people in theBicol Region. The cargo shipLCU Cebu Great Ocean ran aground in the southern Philippines. Overall, Surigae killed at least 10 people and left another eight missing, in addition to causing at least₱272.8 million (US$5.67 million) in damage in the Philippines.
Extratropical cyclone, remnant low, tropical disturbance, or monsoon depressionDuring mid-April 2021, an area ofatmospheric convection associated with a weakarea of low pressure developed roughly 1,150 km (710 mi) south ofGuam. By April 10, the disturbance had acquired nascentrainbands within an environment exhibiting lowwind shear, warmsea surface temperatures (SSTs) between 28–29 °C (82–84 °F), and a well-establishedoutflow, which was conducive for furthertropical cyclogenesis.[5] Showers and thunderstorms continued to emerge around the circulation embedded within the disturbance.[6] TheJapan Meteorological Agency (JMA)[nb 3] assessed the formation of atropical depression near5°N143°E / 5°N 143°E /5; 143; at the time, the newly designated system was moving slowly west-northwest around the southern periphery of asubtropical ridge.[7][8] Due to its anticipated track intoPhilippine waters, thePhilippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) also began issuing advisories on the tropical depression on April 12.[9] TheJoint Typhoon Warning Center (JTWC)[nb 4] issued aTropical Cyclone Formation Alert (TCFA) later that day, projecting a high likelihood of a significant tropical cyclone developing. By April 13, the agency assessed the disturbance as a tropical depression.[7][11]
A strongrainband along the depression's northern semicircle became prominent and coalesced around a robust and developingcentral dense overcast.[11] At 18:00 UTC on the same day, the JMA upgraded the system to atropical storm andnamed itSurigae.[12][13] Surigae was also upgraded to a tropical storm by the JTWC in the early hours of April 14, as the system progressed westward in thePhilippine Sea.[14][15] The storm continued to move slowly, remaining nearly stationary on April 14 – as it gradually intensified.[16][17] Surigae's convective activity was initially displaced to the west of its center of circulation, though additional rainbands and thunderstorm development later covered the central vortex.[18] On April 15, the JMA upgraded Surigae to a severe tropical storm as it moved closer to the island nation ofPalau.[19] A formativeeye became apparent onmicrowave satellite imagery later that day.[20]
By April 16, Surigae strengthened to a typhoon just north of Palau, making it the first typhoon of the 2021 Pacific typhoon season.[21][22] The typhoon's convective activity had become tightly wound around its center, indicating additional strengthening.[23] On April 16 at 03:00 UTC, thePhilippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) gave the storm the local nameBising as it entered thePhilippine Area of Responsibility.[24] The system's eye became apparent through the central overcast, preceding a period ofrapid intensification as Surigae progressed west-northwestward through a conducive environment.[23] Surigae's central dense overcast became colder and better-organized, with a well-defined ring of very coldcloud tops encircling a 26 km (16 mi) diameter eye. Concurrently, an approachingtrough produced a gap in the subtropical ridge of high pressure to the north, causing Surigae to slowly curve northwest as it quickly strengthened.[25]
On April 17, the JMA determined via theDvorak technique that Surigae'sbarometric pressure had rapidly fallen to 895hPa (mbar; 26.43inHg), as the storm reached its peak intensity.[26][27][28] Its 10-minutemaximum sustained winds reached 220 km/h (135 mph) according to the JMA, while one-minute maximum sustained winds reached 315 km/h (195 mph) according to the JTWC, making it equivalent to a Category 5 super typhoon on theSaffir–Simpson scale (SSHWS);[nb 5][3][30] the peak 1-minute sustained winds were also higher for the time of year than any previous typhoon on record.[27] The JTWC also estimated a minimum central pressure of 882 hPa (mbar; 26.05 inHg) for Surigae at the time.[31] Later that day, Surigae began aneyewall replacement cycle causing its eye to become less apparent on satellite imagery and its winds to slightly diminish. The trough to Surigae's north also impeded the typhoon's outflow, resulting in a decrease in environmental favorability for further intensification.[32] On April 18, Surigae finished its eyewall replacement cycle; Surigae acquiredannular characteristics, bearing a symmetrical appearance and a large eye, which was largely surrounded by one largerainband, by the next day.[31]
By April 20, the prevalence of nearby dry air andupwelling of cold waters beneath the slow-moving typhoon caused its winds to decrease further.[33][34] Some reorganization occurred when Surigae began to move north and away from the upwelled waters, with its large eye becoming less ragged;[33] however, additional entrainment of dry air originating from the mid-troposphere overLuzon caused Surigae's structure to degrade further on April 21. Surigae turned northeast away from thePhilippines later that day and weakened further, upon entering an environment with strong westerly winds in the upper troposphere.[35][36] The once large and clear eye disappeared on April 22, leaving behind an increasingly-disheveled cluster of weakening showers and thunderstorms.[37] Soon afterward, all of Surigae's remaining convection was sheared to the east, as the storm moved over cooler waters. As most of the remaining thunderstorms had dissipated, Surigae transitioned into asubtropical cyclone on April 23 due to interacting with an upper-level atmospherictrough as Surigae traversed a cold oceaniceddy.[15] Surigae began to undergoextratropical transition, a process it completed late on April 24, at which time the JTWC issued their final advisory on the system.[14] The JMA declared that Surigae had become extratropical a few hours later.[38]
As an extratropical cyclone, Surigae underwentexplosive cyclogenesis on April 26, with its central pressure falling 44 hPa (mbar; 1.3 inHg) within 24 hours, while rapidly tracking northeastward.[39] While located to the east ofHokkaido, the system's ten-minute maximum sustained winds reached 130 km/h (80 mph) at 18:00 UTC that day,[40] and its central pressure bottomed out at 944 hPa (mbar; 27.88 inHg) six hours later.[41] Late on April 27, Surigae's remnant started to weaken while turning eastward. The next day, the system's forward motion significantly slowed down. On April 30, Surigae underwent a center reformation, with the original center of low pressure dissipating, and a new low-pressure center forming shortly afterward, which quickly dominated the system.[42]
Starting on April 14, theNational Weather Service office inTiyan, Guam began issuing advisories across the Federated States of Micronesia and Palau, withtropical storm watches raised acrossYap andNgulu Atoll ofYap State;[43] both watches were upgraded to warnings the same day as Surigae neared Ngulu Atoll. In addition,Kayangel andKoror in Palau received a tropical storm watch.[44] The warning for Yap was then canceled on April 15.[45] That same day, the watches for Kayangel and Koror were upgraded to warnings.[46] After Surigae had become a typhoon the following day, a typhoon warning was issued for Kayangel.[47] All advisories were canceled on April 17 as Surigae moved away from Palau.[48] In Palau, 350 people were in shelters, including 18 public schools.[49]
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As Surigae entered the Philippine Area of Responsibility, the PAGASA began issuing weather bulletins for the nearby storm. Initial forecasts by the agency suggested that the storm was less likely to make landfall overLuzon, and expected the storm to re-curve away from the Philippines.[24][50][51] On April 16, theDepartment of Transportation of the Philippines suspended all air and land travel to and fromVisayas andMindanao.[52] In the ensuing travel suspension, 2,507 individuals and 61 sea vessels were stranded in ports throughout the country.[53] Wave heights as high as 4.5 m (15 ft) were forecast near the eastern coasts of Visayas and Mindanao.[54] In order to avoid agricultural losses, SecretaryWilliam Dar of theDepartment of Agriculture encouraged farmers in theBicol andEastern Visayas regions to harvest their crops and for fishermen to refrain from fishing due to worsening oceanic conditions.[51][55] At 15:00 UTC (23:00 PHT), the PAGASA began issuingTropical Cyclone Wind Signal (TCWS) #1 for areas in Eastern Visayas and theCaraga Region, as well as for portions of Luzon six hours later.[56][57]
On April 17, TCWS #2 was issued forCatanduanes and the entire island ofSamar.[58] Flood advisories were also issued by the PAGASA for three regions in Visayas and Mindanao.[59] In preparation for the intense rains, theNational Telecommunications Commission ordered telecommunications companies to prepare facilities in forecasted affected areas, including free calling and charging stations.[60][61][62] As early as April 17, preemptive evacuation began in the Bicol Region and theSamar province,[63] and by April 21, 169,072 people were evacuated in theCagayan Valley,Bicol Region,Eastern Visayas, andCaraga. Flights inDaniel Z. Romualdez Airport and all Tacloban Airports were cancelled on April 18, and other domestic flights were also cancelled on the same day.[61] In addition, 10 domestic flights elsewhere were also cancelled that day.[53] Schools and work activities were suspended in the Bicol Region till April 20.[64] The Filipino government prepared₱1.5 billion (US$31.05 million) worth of standby funds for disaster response.[65]
Locally heavy rainfall occurred in parts ofPalau and Yap for several days.[66] Surigae brought sustained winds of up to 80 km/h (50 mph) and gusts up to 135 km/h (84 mph) to Palau, causing power outages across the island.[67][68][69] Large swells from the developing storm broughtcoastal flooding toKoror and Yap. Residents in those areas were advised to avoid reef lines in the north and west, and to take caution on beaches due torip currents and large waves.[70] Surigae was the closest typhoon to pass near the island of Palau sinceTyphoon Haiyan.[71] Restaurants, sporting events and other services were closed in Palau as Surigae approached closer– yet schools remained open.[71] Schools were not suspended until power had been cut off across much of the entire country. Water and cellular services were also downed.[71] 125 homes across the country were destroyed, while at least 1,500 sustained minor damage. The entire population of Palau, consisting of approximately 18,008 people, was impacted by the typhoon.[69] At least US$2 million worth of infrastructure alone was damaged in Palau.[72] The total amount of damage across health, infrastructure, education, food, communication, utilities and other sectors was assessed at US$4.8 million.[69] President of PalauSurangel Whipps Jr. issued anational state of emergency on April 18.[73] TheUnited States Agency for International Development (USAID) provided US$100,000 for immediate assistance to support those affected.[74] InGuam, emergency supplies were being prepared and donated to communities in need in Palau.[73]
Five people in a boat were rescued off the coast ofPujada Bay due to dangerous sea conditions produced by Surigae.[75] Another boat with two fishermen aboard capsized during midnight on its way toBantayan Island, with both of two fishermen having to swim back to shore.[76] On April 19, Surigae forced the cargo shipLCU Cebu Great Ocean, carrying twenty crew members andnickelore, to run aground on the coast of the Province ofSurigao del Norte, in the southern Philippines.[77][78] At least six of the crew members were found dead, while seven were rescued.[79][80] Heavy rain from the outer bands of Surigae battered Eastern Visayas and the Bicol Region as it passed around 345 km (215 mi) to the east of Catanduanes.[81] Widespread rainfall totals of up to 200–300 millimetres (8–12 in) occurred in the eastern Philippines, while 511 millimetres (20.13 in) of rain fell inVirac, Catanduanes and surrounding areas.[82] Afunnel cloud was also briefly reported inCamarines Sur.[83] Twenty-twobarangays were flooded in Eastern Visayas, and in the municipality ofJipapad, flooding reached 4 metres (13 ft). Power interruptions were experienced inCentral Visayas, Eastern Visayas and inEastern Samar, power was interrupted for the whole province.[61] 109,815 people were displaced by flooding and landslides in the Bicol Region.[84]
Ten deaths were reported due to the typhoon. One person inSouthern Leyte and another inCebu died due to fallen coconut trees.[85][86] Six crew members of theLCU Cebu Great Ocean were found dead after the ship ran aground in the southern Philippines.[79][80] Another person remains missing in Northern Samar.[87] 13 others were injured.[85] A total of 3,385 houses were damaged in the Bicol Region, Eastern Visayas and Caraga, with 158 totally destroyed. Agricultural damage in the Bicol Region and Eastern Visayas reached₱261.9 million (US$5.43 million), while infrastructural damage totaled ₱10.87 million (US$226,000).[88] 63 cities experienced power interruptions; however, power was restored in 54 of those cities.[89]
Following the passage of Surigae, theDepartment of Social Welfare and Development (DSWD) andlocal government units provided assistance worth approximately ₱6.52 million (US$135,000) to those affected inCagayan Valley, the Bicol Region and the Eastern Visayas.[88] Schools and workplaces fully reopened by April 20.[90]
The influence of Surigae caused gusts inNorth Sulawesi that reached 23 mph (37 km/h).[91] Large waves of 13.1–19.8 feet (4.0–6.0 m) affected the coastal waters of theSitaro Islands Regency,Sangihe Islands Regency, theTalaud Islands and the northernMolucca Sea.[92]Surigae made its closest approach to Taiwan on April 22. The typhoon's outer bands brought much-needed rainfall to central Taiwan, which was going through its worst drought in 56 years. There were also reports of hail.[93] Large waves up to 4.2 m (14 ft) tall generated by Surigae were recorded along Taiwan's east coast on April 21.[94]
Tropical cyclones of the2021 Pacific typhoon season | ||
|---|---|---|
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