Typhoon Pongsona

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Typhoon Pongsona
Typhoon (JMA)
Category 4 typhoon (SSHS)
Typhoon Pongsona striking Guam

Typhoon Pongsona striking Guam
Formed December 2, 2002
Dissipated December 11, 2002
Highest
winds
175 km/h (110 mph) (10-minute sustained)
240 km/h (150 mph) (1-minute sustained)
Lowest pressure 940 hPa (mbar)
Fatalities 1 indirect
Damage $730 million (2002 USD)
$870 million (2008 USD)
Areas
affected		 Guam, Northern Marianas Islands
Part of the
2002 Pacific typhoon season

Typhoon Pongsona (international designation: 0226, JTWC designation: 31W) was the last typhoon of the 2002 Pacific typhoon season, and was the costliest United States disaster in 2002.[1] The name "Pongsona" was contributed by North Korea for the Pacific tropical cyclone list and is the Korean name for the garden balsam.[2] Pongsona developed out of an area of disturbed weather on December 2, and steadily intensified to reach typhoon status on December 5. On December 8 it passed through Guam and the Northern Marianas Islands while near its peak winds of 175 km/h (110 mph 10-min). It ultimately turned to the northeast, weakened, and became extratropical on December 11.

Typhoon Pongsona produced strong wind gusts peaking at 278 km/h (173 mph 1-min), which left the entire island of Guam without power and destroyed about 1,300 houses. With strong building standards and experience from repeated typhoon strikes, there were no fatalities directly related to Pongsona, although there was one indirect death from flying glass. Damage on the island totaled over $700 million (2002 USD, $800 million 2007 USD), making Pongsona among the five costliest typhoons on the island. The typhoon also caused heavy damage on Rota and elsewhere in the Northern Marianas Islands, and as a result of its impact the name was retired.

Contents

[edit] Storm history

Storm path
Storm path

During late November, an area of convection persisted about 625 kilometers (390 mi) east-southeast of Pohnpei. Satellite imagery indicated broad cyclonic turning in the lower levels of the atmosphere, and a trough was located near the surface.[3] With beneficial outflow aloft, the disturbance developed rainbands as deep convection increased near its mid-level circulation.[4] A low-level circulation formed on December 1, which was initially weak, elongated, and slightly removed from the deep convection.[5] Weak to moderate vertical wind shear allowed the low-level circulation center to consolidate near its cycling convection.[6] Based on its organization, the Japan Meteorological Agency (JMA) classified the system a tropical depression at 0600 UTC on December 2 while it was located 735 km (450 mi) east-northeast of Pohnpei.[7] Shortly thereafter, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert,[6] and at 1800 UTC on December 2 the JTWC classified the system as Tropical Depression 31W.[8]

Upon first becoming a tropical cyclone, the depression tracked northwestward, and in the hours after being classified the circulation became exposed to the east of the deepest convection[9] due to wind shear.[10] The JTWC upgraded the depression to tropical storm status early on December 3,[9] and subsequent to a decrease in the shear the convection redeveloped over the circulation.[10] Accordingly, the JMA upgraded the depression to Tropical Storm Pongsona at 1200 UTC on December 3 while located 375 km (230 mi) northeast of Pohnpei.[7] Located to the south of an upper-level ridge, Pongsona turned westward and gradually intensified.[11] On December 5, the storm developed tightly curved banding features and began forming an eyewall; both the JTWC[12] and the JMA upgraded Pongsona to a typhoon while centered about 1150 km (715 mi) southeast of Guam.[7]

Typhoon Pongsona weakening on December 10
Typhoon Pongsona weakening on December 10

A developing baroclinic system to the east of Japan weakened the subtropical ridge, allowing Typhoon Pongsona to turn to the northwest. Its eye became better defined, and the cyclone continued to gradually intensify.[13] By late on December 7 it developed a well-defined 55 km (35 mi) wide eye as it approached Guam,[14] and the next day the JTWC assessed Pongsona as a 240 km/h (150 mph 1-min winds) supertyphoon, its peak intensity. At 0500 UTC on December 8 the eyewall made landfall on Guam.[15] Shortly thereafter, the JMA estimated Pongsona attained a peak intensity of 175 km/h (110 mph 10-min winds) just to the north of Guam.[7] The typhoon turned to the north-northwest through a weakness in the subtropical ridge a short distance west of the Northern Marianas Islands. On December 9, convection began to weaken as Pongsona began interacting with a mid-latitude system to its north.[16] Dry air became entrained in the north and western portion of the circulation;[17] the eyewall steadily deteriorated, and the low-level circulation became exposed to the west of the diminishing convection.[17] As a result, both the JTWC and the JMA declared Pongsona as an extratropical cyclone on December 11 about 1400 km (865 mi) northwest of Wake Island.[2]

[edit] Differences among warning centers

The Japan Meteorological Agency uses 10-minute sustained winds, while the Joint Typhoon Warning Center uses 1-minute sustained winds. The conversion factor between the two is 1.14.[18] JMA's peak intensity for Pongsona was 170 km/h (105 mph) 10-minute sustained, or 195 km/h (120 mph) 1-minute sustained. The JTWC's peak intensity for Pongsona was 240 km/h (150 mph) 1-minute sustained, or 210 km/h (130 mph) 10-minute sustained. The National Meteorological Center of China estimated a peak intensity of 185 km/h (115 mph) 10-minute sustained, or 210 km/h (135 mph) 1-minute sustained.[2]

[edit] Preparations

The Guam National Weather Service issued a tropical storm watch for the Marshall Islands shortly after Pongsona developed into a tropical storm, and a day later watches were issued for Chuuk. On December 5, the service issued tropical storm warnings for all of the Federal States of Micronesia.[19] As Pongsona became a typhoon, the Guam National Weather Service issued a typhoon watch for Guam, Rota, Saipan, and Tinian, which was upgraded to a typhoon warning about 23 hours prior to the onset of typhoon-force winds; typhoon warnings were also issued for the unpopulated island of Agrihan. By one day before the typhoon moved through the Mariana Islands, local weather offices predicted Pongsona to pass well east of the area. Despite a more westward track than anticipated, forecasts remained stagnant until the morning of December 8, when two lead forecasters reluctantly predicted much greater threat to the Mariana Islands. As a result, many citizens felt they were unprepared and insufficiently warned for the typhoon.[19]

Nine shelters throughout the Northern Mariana Islands were opened to accommodate families needing assistance. Several schools opened classrooms as evacuation centers.[20] On Guam, ten schools were used as shelters,[21] and on the day of impact 2,271 people were in shelters. On Rota, 159 people sought shelter, and in Saipan, 549 were in shelters by the day of impact.[22] The Guam Memorial Hospital officials advised all pregnant mothers within 32 weeks of their delivery date to check in. The Guam Office of Civil Defense filed the paperwork for the Federal Emergency Management Agency to declare the island a disaster area. Governor Carl T.C. Gutierrez took similar measures to declare a state of emergency for the area.[21] Following experience from previous typhoons, Guam newspaper Pacific Daily News underwent preparations to provide internet updates for the storm, including reinforcing the building, maintaining sufficient food supplies for the staff, and stationing two reporters elsewhere on the island; the paper was the only immediate source of information about the typhoon outside of Guam.[23]

[edit] Impact

[edit] Federal States of Micronesia

Early in its duration, Pongsona first affected Pohnpei as a tropical storm. There, it produced heavy rains and gusty winds, though little damage was reported. Later, it brought tropical storm force winds to Chuuk. High waves from the storm washed over and covered some atolls.[19]

[edit] Guam

Damage from Pongsona on Guam
Damage from Pongsona on Guam

Typhoon Pongsona maintained a 65 km (40 mi) wide eye upon crossing the northern, populated portion of the island of Guam; the Andersen Air Force Base was in the eye for two hours. Sustained winds from the typhoon peaked at 232 km/h (144 mph) with gusts peaking at 278 km/h (173 mph); gusts of at least 160 km/h (100 mph) affected the entire island. The lowest pressure on the island was 935 millibars (27.61 inHg), making Pongsona the third most intense typhoon to strike Guam; it is behind only a typhoon in 1900 (926 mbar, 27.34 inHg) and Typhoon Karen of 1962 (932 mbar, 27.52 inHg).[19]

Communications on the island failed due to the winds;[19] the entire island was left without power and phone service.[24] The winds greatly damaged 715 power poles and 513 transformers, leaving about $52 million in electrical damage reported (2002 USD, $59 million 2007 USD).[22] The local weather office's communication link was cut off after flooding damaged a telecommunication facility, causing the National Weather Service in Honolulu, Hawaii to provide backup support by temporarily issuing warnings and advisories. Many anemometers near the northern coastline failed from the winds.[19] The winds collapsed several walls at the Guam Memorial Hospital, resulting in major damage throughout the northern two-thirds of the facility and several units being shut down. Several hotels, churches, and schools received moderate damage, and the Antonio B. Won Pat International Airport received damage to navigation equipment.[22] Typhoon Pongsona also left 65% of the island's water wells inoperable,[22] with most of Guam left without water service following the storm.[24] Officials estimate the typhoon destroyed 1,300 homes, severely damaged 1,825, and lightly damaged 4,800.[25]

Damage in Guam from typhoon
Damage in Guam from typhoon

Tracking slowly across the center of the island, the intense inner rainbands dropped heavy rainfall which peaked at 650 mm (25.61 in) at the University of Guam.[19] The precipitation led to record river flow on the Pago and Asan Rivers; overflown rivers caused damage to some roads and bridges. The rainfall also caused extensive flooding in several villages. Pongsona produced a storm surge of up to 6 m (20 ft) at some locations, with 3 – 4 m (9 – 13 ft) recorded near the eyewall. Considerable storm surge flooding occurred from Tumon southward to Piti, leaving some buildings on the west coast of the island flooded with 1 m (4 ft) of water. The combination of strong storm surge and rough waves caused considerable beach erosion and severe coastal damage.[22]

Across Guam, damage totaled over $700 million (2003 USD, $800 million 2007 USD), placing it among the five costliest typhoons on the island. The typhoon injured 193 people, as reported by the Guam Department of Health; most were lacerations and fractures caused by flying glass and other debris. There was one indirect death attributed to the storm, when a 71-year old woman was cut by flying glass and subsequently suffered a fatal heart attack; medical help could not reach her due to the intensity of the storm. As six typhoons had passed directly over the island during the previous ten years, officials in Guam enacted strong building standards, keeping deaths and injuries to a minimum. The typhoon was considered by the public the worst typhoon to ever strike the island due to the large eye affecting most of the population.[19]

[edit] Northern Mariana Islands

Typhoon damage on Rota
Typhoon damage on Rota

Pongsona produced sustained winds of 126 km/h (78 mph) with a gust to 137 km/h (85 mph) on Rota. The combination of winds and other effects from the typhoon destroyed 114 houses, severely damaged 154, and caused minor damage to 306; on the island, about 200 families were left homeless. The typhoon produced a storm surge of 6.7 m (22 ft) at Songsong Village, which crossed about 80% of the southwestern peninsula on Rota. The surge caused moderate beach erosion on the island, and destroyed a fuel pier and a loading pipeline. Additionally, the typhoon caused severe crop damage on the island. In all, the typhoon caused ten minor injuries on Rota, and resulted in over $30 million in damage (2002 USD, $34 million 2007 USD).[22]

On Tinian, the passage of Pongsona destroyed two homes; seven received major damage and another eight sustained minor damage. The winds damaged power lines, causing two island-wide power outages. Major crop damage was reported.[22]

On Saipan, two houses were destroyed and fifteen were damaged, of which seven severely. Sustained winds on the island peaked at 71 km/h (44 mph), which caused scattered power outages. Six minor injuries were reported, and damage totaled about $100,000 (2002 USD, $114,000 USD 2007 USD).[22]

[edit] Aftermath

Gas tank fire on Cabras Island
Gas tank fire on Cabras Island

On the same day of Typhoon Pongsona striking Guam, President George W. Bush declared the island a major disaster area.[26] Around the time of the cyclone passing over the island, 2,271 residents were in shelters, and by the next day it increased to 3,467 after people discovered their homes were uninhabitable.[22] With thirteen Red Cross shelters across Guam,[27] most remained in shelters for about three weeks before disaster tents were distributed.[22] The American Red Cross worked with the United States Department of Agriculture to provide meals for shelter attendees for a two week period following the typhoon.[27] Through the collaboration of federal and other agencies, disaster assistance on Guam totaled over $300 million (2003 USD, $335 million 2007 USD) by 100 days after the typhoon struck, including $60 million (2002 USD, $67 million 2007 USD) in initial disaster response. Nearly 29,000 individuals registered for disaster assistance, with the first assistance check arrived ten days after the disaster declaration. By three months after the storm, the United States Small Business Administration approved $130 million (2003 USD, $145 million 2007 USD) in low-interest loans.[1]

During the height of the typhoon at Cabras Island on Guam, a gasoline tank caught fire, believed to be from friction caused by extremely high winds running through its ventilation system. The tank exploded, sending its lid airborne and spreading the fire to other nearby tanks. The proximity of the tanks as well as low water pressure hampered firefighting efforts, and the fire was extinguished five days later; it resulted in three destroyed gasoline tanks with two more caught on fire.[22] While the fire was burning, transportation of gasoline from the port to the rest of Guam was suspended resulting in a halt in gasoline sales for the general public.

On December 11, 2002, President Bush extended the disaster declaration to include the Northern Marianas Islands, which allocated emergency disaster aid for the territory. The declaration provided funding for 75% of the budget for debris removal and emergency protective measures.[28] Immediately following the typhoon, FEMA assigned various federal agencies to respond to the island of Rota. Officials airlifted about 3,600 kg (8,000 lbs) of emergency supplies including tents, tarps, water containers, coolers, cooking kits and electrical equipment. Military personnel were transported to assist in recovery efforts. By four months after the typhoon, 749 individuals on the island registered through FEMA's teleregistration number. The United States Small Business Administration approved 147 low – interest loans for $9.1 million (2003 USD, $10.2 million 2007 USD) to individuals and businesses and for economic injury on Rota. In all, disaster aid to Rota totaled $17.4 million (2003 USD, $19.4 million 2007 USD).[29] Additionally, President Bush authorized disaster assistance for the Federated States of Micronesia.[30]

Due to the damage resulted from the storm, the name Pongsona was retired during the 38th session of the Economic and Social Commission for Asia and the Pacific and World Meteorological Organization typhoon committee in November 2005; it was replaced with the name Noul.[31]

[edit] See also

Tropical cyclones Portal

[edit] References

  1. ^ a b Federal Emergency Management Agency (2003). Super Typhoon Pongsona: The First 100 Days Over $300 Million In Disaster Relief And Assistance. Retrieved on 2007-07-27.
  2. ^ a b c Gary Padgett (2003). Tropical Cyclone Summary for December 2002. Retrieved on 2006-07-19.
  3. ^ Bryant et al. (2002). November 30 Significant Tropical Weather Advisory. Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  4. ^ Smith et al. (2002). November 30 Significant Tropical Weather Advisory (2). Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  5. ^ Bryant et al. (2002). December 2 Significant Tropical Weather Advisory. Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  6. ^ a b Bryant et al. (2002). December 2 Significant Tropical Weather Advisory (2). Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  7. ^ a b c d Japan Meteorological Agency (2002). 2003 Western Pacific Tropical Summary (PDF). Retrieved on 2006-07-19.
  8. ^ Waugaman (2002). Tropical Depression 31W (SW of Kwajalein). Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  9. ^ a b Joint Typhoon Warning Center (2002). Tropical Storm 31W Warning NR 002. Retrieved on 2007-06-19.
  10. ^ a b Lam (2002). Tropical Storm 31W. Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  11. ^ Wingeart et al. (2002). Tropical Storm Pongsona Prognostic Reasoning 004. Joint Typhoon Warning Center. Retrieved on 2007-06-19.
  12. ^ Joint Typhoon Warning Center (2002). Typhoon 31W (Pongsona) Warning NR 011. Retrieved on 2007-06-19.
  13. ^ Leejoice et al. (2002). Typhoon Pongsona Prognostic Reasoning 018. Joint Typhoon Warning Center. Retrieved on 2007-06-20.
  14. ^ Joint Typhoon Warning Center (2002). Typhoon 31W (Pongsona) Warning NR 022. Retrieved on 2007-06-19.
  15. ^ Joint Typhoon Warning Center (2002). Typhoon 31W (Pongsona) Warning NR 023. Retrieved on 2007-06-19.
  16. ^ Wingeart et al. (2002). Typhoon Pongsona Prognistic Reasoning 028. Joint Typhoon Warning Center. Retrieved on 2007-06-20.
  17. ^ a b Bryant et al. (2002). Typhoon Pongsona Prognostic Reasoning 030. Joint Typhoon Warning Center. Retrieved on 2007-06-20.
  18. ^ Joint Typhoon Warning Center (2005). Frequently Asked Questions.
  19. ^ a b c d e f g h John J. Kelly Jr. (2003). Super Typhoon Pongsona Service Assessment (PDF). United States Departent of Commerce. Retrieved on 2006-10-07.
  20. ^ Saipan Tribune. "Residents told: Prepare for typhoon". Retrieved on 2006-10-07. 
  21. ^ a b Sabina Salas (2002). Brace for impact:Pongsona to hit Guam and Rota this afternoon. KUAM. Retrieved on 2006-10-07.
  22. ^ a b c d e f g h i j k National Climatic Data Center (2003). Event Report for Typhoon Pongsona. Retrieved on 2006-10-10.
  23. ^ FEMA (2003). When the Media is a Disaster Victim: How one small Paper kept the world informed. Retrieved on 2006-10-07.
  24. ^ a b Federal Emergency Management Agency (2003). Update on Recovery Efforts in Guam and Rota following Super Typhoon Pongsona (DOC). Retrieved on 2007-06-29.
  25. ^ Bonnie Gillespie (2002). Hope Prevails Amid Complex Recovery in Guam. RedCross.org. Retrieved on 2007-07-23.
  26. ^ Federal Emergency Management Agency (2002). President Declares Major Disaster For Guam Typhoon. Retrieved on 2007-06-29.
  27. ^ a b FEMA (2002). Coordinating Massive Federal Aid For Guam. Retrieved on 2007-07-23.
  28. ^ FEMA (2002). President Orders Disaster Aid For Northern Mariana Islands Typhoon Response. Retrieved on 2007-07-23.
  29. ^ FEMA (2003). CNMI Disaster Assistance Tops $17 Million For Typhoon Pongsona. Retrieved on 2007-07-23.
  30. ^ FEMA (2003). President Declares Major Disaster For Micronesia. Retrieved on 2007-07-23.
  31. ^ ESCAP/WMO Typhoon Committee (2005). 38th Session of the Typhoon Committee. Retrieved on 2007-07-27.
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Retired Pacific typhoon names by the Japan Meteorological Agency
2000s
Vamei (TS) • Chataan • Rusa • Pongsona • Imbudo • Maemi • Sudal • Rananim • Matsa • Nabi • Longwang • Chanchu • Bilis (TS) • Saomai • Xangsane • Durian
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