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Cyclone Ofa
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Cyclone Ofa
Severe Tropical Cyclone Ofa was a powerful tropical cyclone that caused severe damage in Polynesia in February 1990. The system was first noted on January 27, 1990, near Tuvalu, as a shallow tropical depression that had developed within the South Pacific Convergence Zone. The cloud pattern slowly organized, and on January 31, while located east of Tuvalu, Ofa attained cyclone intensity. Moving slowly southeast, Ofa developed storm-force winds. It attained hurricane-force winds on February 2. Cyclone Ofa reached peak intensity on February 4. Shortly after, its peak Ofa began to weaken over a less favourable environment. Ofa was declared an extratropical cyclone on February 8, though the system was still tracked by meteorologists until February 10.
Ofa produced gales or high winds or gales on many islands, resulting in widespread damage due to a combination of storm surge and high seas. In all, eight people were killed and damage totaled to US$187 million. The worst effects were recorded in Samoa, where seven people were killed. Roughly 200 people were evacuated, and 10 to 20 others were injured through the islands. Extreme damage to crops and trees was also recorded. Elsewhere, Ofa was blamed for the lowest ever recorded pressure on the island of Niue, along with considerable damage.
Towards the end of January 1990, a surge in the Northern Hemisphere's trade winds and the Southern Hemispheres monsoon, led to the South Pacific Convergence Zone (SPCZ) and the Australian monsoon trough becoming active after a prolonged period of dormancy. As a result, two shallow tropical depressions were spawned; one over the Coral Sea that went on to become Cyclone Nancy, while the other was first noted within the SPCZ over Tuvalu on January 27. Over the next two days the system developed little and remained slow moving, near the Tuvaluan atoll of Funafuti. During January 30, the depression moved towards the north-east and started to organize, as pressures near the systems center rapidly falling. During the next day the system subsequently started to curve south-eastwards and away from Tuvalu, before the United States Naval Western Oceanography Center (NWOC) initiated advisories on the system and designated it as Tropical Cyclone 13P during January 31. At 19:17 UTC on January 31, Fiji Meteorological Service named the system Ofa, after it had developed into a category 1 tropical cyclone on the Australian tropical cyclone intensity scale.
As it was named the system was located about 300 km (185 mi) to the east of Tuvalu and had started to curve more towards the south-southeast. During February 1, as Ofa started to affect Western Samoa, the NWOC reported that Ofa had become equivalent to a category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale (SSHWS).
The FMS subsequently reported during the next day that the system had become a category 3 severe tropical cyclone. Ofa passed about 110 km (70 mi) to the west of the Western Samoan Island of Savai'i between 10:00 and 18:00 UTC during February 3. Early the next day as the system started to accelerate towards the south-southeast towards the island nation of Niue, the NWOC estimated that Ofa had peaked with 1-minute sustained wind speeds of 215 km/h (130 mph), which made it equivalent to a category 4 hurricane on the SSHWS. Later that day the FMS estimated that the system had peaked as a category 4 severe tropical cyclone, with 10-minute sustained wind speeds of 185 km/h (115 mph). Early on February 5, Ofa started to show signs that it had started to weaken, as it passed about 55 km (35 mi) to the west of Niue. Over the next day the system slowly weakened as it moved southwards, before late on February 6, the FMS passed the primary warning responsibility for Ofa to the New Zealand Meteorological Service, after the system had moved below 25°S. The system subsequently weakened very quickly and started to transition into an extratropical cyclone, as it encountered strong upper level winds and cooler waters. The system completed this transition during February 8, before the remnants were last noted during February 10 after they had performed a small clockwise loop.
Cyclone Ofa was considered to be the worst tropical cyclone to affect Polynesia since Severe Tropical Cyclone Bebe in 1972. The system affected seven different island nations and caused gales or much stronger winds in six of those countries, which resulted in damage ranging from moderate to very severe. Storm tide from the cyclone which is the combined effect of storm surge and high tide caused havoc in several countries and was the major cause of destruction. Overall the system killed at least eight people while it was estimated that the overall damage would amount to over US$180 million with damage totals of at least US$150 million and US$30 million in Western and American Samoa.
The island nation of Tuvalu was affected by Severe Tropical Cyclone Ofa during February 1, with strong to gale-force winds causing a major impact on the island nation, along with the Samoa depression that affected the islands a few days later. The majority of the islands reported damage to vegetation and crops, such as bananas, coconuts and breadfruits. Staff housing and a chapel on a government secondary school campus were up-roofed and collapsed, while a supermarket building collapsed as a result of heavy swells. On Vaitupu Island around 85% of residential homes, trees and food crops were destroyed, while residential homes were also destroyed on the islands of Niutao, Nui and Nukulaelae. On Funafuti sea waves flattened the Hurricane Bebe bank at the southern end of the airstrip, which caused sea flooding and prompted the evacuation of several families from their homes. In Nui and Niulakita there was a minor loss of the landscape because of sea flooding while there were no lives lost. After the systems had impacted Tuvalu, a Disaster Rehabilitation Sub-Committee was appointed to evaluate the damage caused and make recommendations to the National Disaster Committee and to the Cabinet on what should be done to help rehabilitate the affected areas. Emergency food aid and other humanitarian relief assistance was received from donors and the Red Cross. The total cost of reconstruction in the island nation was estimated to have exceeded $US1 million.
During January 31, after Ofa's precursor depression had remained near the edge of its area of responsibility for a few days, the Wallis and Futuna Meteorological Service decided to inform local authorities about the system and their expectations for it to develop further. During the next day, after the system had been named Ofa, the FMS issued a tropical cyclone alert, before a yellow alert was triggered as the system was expected to intensify further and impact both islands. During February 2, the FMS issued a gale warning for Wallis while maintaining the alert for Futuna, as it was expected to pass near enough to Wallis to cause gale-force winds on the island. After the system continued to move southwards and had become a severe tropical cyclone it triggered the declaration of a red alert as well as the Organization of the Civil Security Response plan for the whole of the territory. It was subsequently decided to put the satellite telecommunication antenna into its survival position, which as a result meant that Wallis and Futuna were cut off from the international telecommunication network. The system subsequently passed about 240 km (150 mi) to the east of the island and produced gale-force winds on the island for a brief period during that day. Despite numerous objections residents were evacuated from the east coast of Wallis, as high seas, heavy swell and a storm surge of about 1 metre (3.3 ft) above the astronomical tide caused flooding on the east coast of Wallis. Minor damages to trees, houses, plantations of yams and taros, government buildings and village roads was reported, while no there were no deaths or casualties reported on Wallis.
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Cyclone Ofa
Severe Tropical Cyclone Ofa was a powerful tropical cyclone that caused severe damage in Polynesia in February 1990. The system was first noted on January 27, 1990, near Tuvalu, as a shallow tropical depression that had developed within the South Pacific Convergence Zone. The cloud pattern slowly organized, and on January 31, while located east of Tuvalu, Ofa attained cyclone intensity. Moving slowly southeast, Ofa developed storm-force winds. It attained hurricane-force winds on February 2. Cyclone Ofa reached peak intensity on February 4. Shortly after, its peak Ofa began to weaken over a less favourable environment. Ofa was declared an extratropical cyclone on February 8, though the system was still tracked by meteorologists until February 10.
Ofa produced gales or high winds or gales on many islands, resulting in widespread damage due to a combination of storm surge and high seas. In all, eight people were killed and damage totaled to US$187 million. The worst effects were recorded in Samoa, where seven people were killed. Roughly 200 people were evacuated, and 10 to 20 others were injured through the islands. Extreme damage to crops and trees was also recorded. Elsewhere, Ofa was blamed for the lowest ever recorded pressure on the island of Niue, along with considerable damage.
Towards the end of January 1990, a surge in the Northern Hemisphere's trade winds and the Southern Hemispheres monsoon, led to the South Pacific Convergence Zone (SPCZ) and the Australian monsoon trough becoming active after a prolonged period of dormancy. As a result, two shallow tropical depressions were spawned; one over the Coral Sea that went on to become Cyclone Nancy, while the other was first noted within the SPCZ over Tuvalu on January 27. Over the next two days the system developed little and remained slow moving, near the Tuvaluan atoll of Funafuti. During January 30, the depression moved towards the north-east and started to organize, as pressures near the systems center rapidly falling. During the next day the system subsequently started to curve south-eastwards and away from Tuvalu, before the United States Naval Western Oceanography Center (NWOC) initiated advisories on the system and designated it as Tropical Cyclone 13P during January 31. At 19:17 UTC on January 31, Fiji Meteorological Service named the system Ofa, after it had developed into a category 1 tropical cyclone on the Australian tropical cyclone intensity scale.
As it was named the system was located about 300 km (185 mi) to the east of Tuvalu and had started to curve more towards the south-southeast. During February 1, as Ofa started to affect Western Samoa, the NWOC reported that Ofa had become equivalent to a category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale (SSHWS).
The FMS subsequently reported during the next day that the system had become a category 3 severe tropical cyclone. Ofa passed about 110 km (70 mi) to the west of the Western Samoan Island of Savai'i between 10:00 and 18:00 UTC during February 3. Early the next day as the system started to accelerate towards the south-southeast towards the island nation of Niue, the NWOC estimated that Ofa had peaked with 1-minute sustained wind speeds of 215 km/h (130 mph), which made it equivalent to a category 4 hurricane on the SSHWS. Later that day the FMS estimated that the system had peaked as a category 4 severe tropical cyclone, with 10-minute sustained wind speeds of 185 km/h (115 mph). Early on February 5, Ofa started to show signs that it had started to weaken, as it passed about 55 km (35 mi) to the west of Niue. Over the next day the system slowly weakened as it moved southwards, before late on February 6, the FMS passed the primary warning responsibility for Ofa to the New Zealand Meteorological Service, after the system had moved below 25°S. The system subsequently weakened very quickly and started to transition into an extratropical cyclone, as it encountered strong upper level winds and cooler waters. The system completed this transition during February 8, before the remnants were last noted during February 10 after they had performed a small clockwise loop.
Cyclone Ofa was considered to be the worst tropical cyclone to affect Polynesia since Severe Tropical Cyclone Bebe in 1972. The system affected seven different island nations and caused gales or much stronger winds in six of those countries, which resulted in damage ranging from moderate to very severe. Storm tide from the cyclone which is the combined effect of storm surge and high tide caused havoc in several countries and was the major cause of destruction. Overall the system killed at least eight people while it was estimated that the overall damage would amount to over US$180 million with damage totals of at least US$150 million and US$30 million in Western and American Samoa.
The island nation of Tuvalu was affected by Severe Tropical Cyclone Ofa during February 1, with strong to gale-force winds causing a major impact on the island nation, along with the Samoa depression that affected the islands a few days later. The majority of the islands reported damage to vegetation and crops, such as bananas, coconuts and breadfruits. Staff housing and a chapel on a government secondary school campus were up-roofed and collapsed, while a supermarket building collapsed as a result of heavy swells. On Vaitupu Island around 85% of residential homes, trees and food crops were destroyed, while residential homes were also destroyed on the islands of Niutao, Nui and Nukulaelae. On Funafuti sea waves flattened the Hurricane Bebe bank at the southern end of the airstrip, which caused sea flooding and prompted the evacuation of several families from their homes. In Nui and Niulakita there was a minor loss of the landscape because of sea flooding while there were no lives lost. After the systems had impacted Tuvalu, a Disaster Rehabilitation Sub-Committee was appointed to evaluate the damage caused and make recommendations to the National Disaster Committee and to the Cabinet on what should be done to help rehabilitate the affected areas. Emergency food aid and other humanitarian relief assistance was received from donors and the Red Cross. The total cost of reconstruction in the island nation was estimated to have exceeded $US1 million.
During January 31, after Ofa's precursor depression had remained near the edge of its area of responsibility for a few days, the Wallis and Futuna Meteorological Service decided to inform local authorities about the system and their expectations for it to develop further. During the next day, after the system had been named Ofa, the FMS issued a tropical cyclone alert, before a yellow alert was triggered as the system was expected to intensify further and impact both islands. During February 2, the FMS issued a gale warning for Wallis while maintaining the alert for Futuna, as it was expected to pass near enough to Wallis to cause gale-force winds on the island. After the system continued to move southwards and had become a severe tropical cyclone it triggered the declaration of a red alert as well as the Organization of the Civil Security Response plan for the whole of the territory. It was subsequently decided to put the satellite telecommunication antenna into its survival position, which as a result meant that Wallis and Futuna were cut off from the international telecommunication network. The system subsequently passed about 240 km (150 mi) to the east of the island and produced gale-force winds on the island for a brief period during that day. Despite numerous objections residents were evacuated from the east coast of Wallis, as high seas, heavy swell and a storm surge of about 1 metre (3.3 ft) above the astronomical tide caused flooding on the east coast of Wallis. Minor damages to trees, houses, plantations of yams and taros, government buildings and village roads was reported, while no there were no deaths or casualties reported on Wallis.
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