Cyclone Ron

Severe Tropical Cyclone Ron

Category 5 cyclone (Australian scale) Category 5 Tropical cyclone (SSHWS)
Cyclone Ron at peak intensity after recurving towards Tonga
Formed	January 1, 1998
Dissipated	January 9, 1998 Absorbed by Cyclone Susan.
Highest winds	10-minute sustained: 230 km/h (145 mph) 1-minute sustained: 270 km/h (165 mph)
Lowest pressure	900 mbar (hPa); 26.58 inHg
Fatalities	None
Damage	$566,000 (1998 USD)
Areas affected	Samoan islands, Tonga, Wallis and Futuna
Part of the 1997–98 South Pacific cyclone season

Severe Tropical Cyclone Ron was one of the most intense tropical cyclones of the ever recorded in the South Pacific. Ron was the sixth named storm of the 1997-98 South Pacific cyclone season and the third to form during an active phase of the intraseasonal oscillation in the South Pacific Ocean.^[1] A tropical depression formed on January 1, 1998 northeast of Samoa. Tropical cyclone intensity was reached on January 2 and intensification proceeded at a fairly rapid rate. Ron reached the peak intensity of 145 mph (225 km/h) on January 5, becoming one of the most intense cyclones in the Southern hemisphere in that decade, when Ron was at north-northwest of Apia, Samoa, three days after initial development. The cyclone maintained this strength for about 36 hours, while re-curving to the south-southeast. Then, Ron started weakening while passing between central Tonga and Niue on January 7. Finally, by January 9, Ron was absorbed by the much larger circulation of Severe Tropical Cyclone Susan.^[1]

Meteorological history

On January 1, during an active phase of the intraseasonal oscillation in the basin, the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi) reported that a tropical depression had developed about 850 km (530 mi) to the northeast of Samoa.^[1][2] During that day the depression gradually developed further before the Joint Typhoon Warning Center (JTWC) issued a tropical cyclone formation alert on the system.^[3] At 0000 UTC on January 2, the JTWC designated the cyclone as Tropical Cyclone 10P with 1-minute wind speeds of 65 km/h (40 mph),^[4] while RSMC Nadi designated it as a tropical cyclone.^[2] Ron steadily intensified for 3 days at a faster-than-average pace, passing near Swains Island on January 3 as a category 1 tropical cyclone on the Australian Scale.^[5][6] On early January 5, Ron passed 110 mi (180 km) southeast of Wallis island as a Category 5 tropical cyclone (Category 4, according to JTWC^[4]), however, because of this cyclone's small wind radius, Wallis reported 10-min average winds of only 20 mph (32 km/h) with gusts to 37 mph (60 km/h).^[5] Six hours later, RSMC Nadi reported that Ron reached its peak 10-minute sustained wind speeds of 145 mph (225 km/h) and a minimun pressure of 900 hPa (26.58 inHg) at 0600 UTC on January 5, about 225 mi (360 km) north-northwest of Apia, Samoa's capital and biggest city.^[1][2] It was the first time that a tropical cyclone of such intensity was observed in the Southern Pacific Ocean since 1985's Cyclone Hina in the 1984-85 South Pacific cyclone season.^[1][2][5] Six hours later, the JTWC reported that the cyclone reached at its peak 1-minute sustained wind speeds of 165 mph (270 km/h) while recurving to a southeastly direction. According to JTWC, Ron maintained that strength for 18 hours.^[4]

Cyclone Ron being absorbed by Cyclone Susan

According to RSMC Nadi, six hours after Ron attained its peak intensity, it took to a south-southwesterly course for about 18 hours until Ron recurved and began moving in a south-southeasterly direction.^[2] 36 hours after it had peaked in intensity RSMC Nadi reported that Ron started weakening as it passed very close to the Tongan island of Niuafo'ou, whre it caused catastrophic damages, destroying almost all houses and agriculture.^[1][2][6] Meanwhile JTWC downgraded it to a Category 4 tropical cyclone on the Saffir-Simpson Hurricane Scale.^[4] The Nadi discussion at 0800 UTC January 6 mentioned that based on winds reported by Niuafo'ou, Ron may have had an even smaller gale radius and stronger winds near the center than had been thought.^[1][5] After passing close of Niuafo'ou Ron began to weaken steadily as it started to accelerate to the southeast. The storm passed between central Tonga and Niue on January 7 as a low-end Category 5 tropical cyclone, hours later being downgraded to a Category 4 in the Australian Scale.^[6] At that time, the JTWC reported that Ron was a Category 3 tropical cyclone in the SSHS, still weakening.^[4]

Then, Ron accelerated to the southeast and weakened until it lost its tropical characteristics and was declared post-tropical by Nadi at 1800 UTC January 8.^[6] By0000 UTC on January 9, Ron had been completely absorbed by Susan as the JTWC issued its final advisory on the cyclone, before the final advisories on the combined system, were released later that day as it lost its tropical characteristics and started to become extratropical.^[2][7] The remnants of the combined system were then monitored for another day, until they were last noted during January 10, bringing an unseasonable cold snap to New Zealand.^[8][9]

Impact

Wallis and Futuna

Cyclone Ron was the fourth and final tropical cyclone to affect the French territory of Wallis and Futuna during 1997 and 1998, after cyclones Gavin, Hina and Keli had affected the islands.^[10][11][12] Ron affected the islands between January 4–6, with waves damaging coastal roads while high winds of up to 130 km/h (80 mph) destroyed several fales and food crops.^[12] The telephone network was also heavily degraded.^[13]

Tonga

Despite being a relatively small cyclone, Ron caused major damage to northern parts of the Tongan group as it crossed the Niuafo'ou, Niuatoputapu and Tafahi islands.^[14] According to BoM, Niuafo'ou island reported sustained winds of 69 mph (111 km/h) with a pressure of 983.7 hPa (29.05 inHg) with peaks of 972.4 hPa (28.71 inHg) and estimated maximum winds from 78 to 89 mph (126 to 143 km/h).^[1]

According to the report made by a survey sent to the affected islands, the cyclone left 99 families without home and 43 ones in need of tarpaulins to repair damages, most of them in the Niuafo'ou island.^[14] Also, Ron's winds caused extensive damage to agriculture and vegetation of the islands, in which includes total loss of fruit and breadfruit trees and severe damage to cassava and banana crops.^[14]

Aftermath and records

Ron's destructive winds caused severe damage in Tonga's sanitation systems, increasing the danger of an outbreak of infectious diseases. Approximately 30% of the water tanks and 95% of the catchment covers had been damaged, leading to a water shortage.^[14] Also, according to Tonga's National Disaster Relief Committee, the great loss of plantations and vegetation led to a six-month food shortage.^[15] Replanting programmes took up to 6–8 months to restore all the lost vegetation.^[14]

Several governments and organizations assisted the people affected by Ron. The Office for the Coordination of Humanitarian Affairs as allocated an Emergency Cash Grant of US$20,000 of relief items and coverage of transportation costs. The Government of New Zealand has provided temporary shelters and assistance with repairs to Government and public health buildings, as well as assistance with replanting with a total value of NZ$36,500 (approximately US$21,340). The United Kingdom provided supplies for the repair of water and sanitary systems of a total value of approximately £15,000 (US$25,000).^[14] The South Pacific Forum Secretariat in Fiji also helped Tonga, releasing US$10,000 from a special disaster fund.^[16]

At that time, Cyclone Ron was the most intense tropical cyclone ever recorded in the South Pacific basin, with a lowest central pressure estimated at 900 hPa (26.58 inHg), but now it is the second most intense, only behind 2002's Cyclone Zoe and tied with its twin, Cyclone Susan and 2005's Cyclone Percy.^[8]

However, according to JTWC's annual report, Ron's lowest pressure was 892 hPa (26.3 inHg),^[3] what would make this cyclone, not only the second strongest cyclone in the South Pacific, but the second strongest cyclone ever recorded in the Southern Hemisphere, only behind Zoe.^[8][17][18] But these measures are unofficial.

Due to the impact of this storm, the name Ron was retired from the lists of tropical cyclone names.^[19]

See also

• Cyclone Susan
• List of the most intense tropical cyclones

References

External links

• World Meteorological Organization
• Fiji Meteorological Service
• Meteorological Service of New Zealand
• Joint Typhoon Warning Center

v t e Retired South Pacific tropical cyclone names 1970s Rosie Wendy Vivienne Agatha Bebe Carlotta Lottie Alison Elsa Marion Bob Charles Diana Fay Gordon Meli Robert Tina Wally 1980s Eddie Tahmar Gyan Issac Joti Lisa Mark Oscar Veena Nigel Eric Harry Ima Namu Raja Sally Tusi Uma Anne Bola Lili 1990s Ofa Peni Sina Tia Val Wasa Betsy Esau Fran Joni Kina Prema Rewa Theodore William Beti Drena Gavin Hina Keli Martin Osea Ron Susan Tui Ursula Veli Cora Dani Frank 2000s Kim Paula Sose Trina Waka Zoe Ami Beni Cilla Heta Ivy Meena Nancy Olaf Percy Cliff Daman Funa Gene Mick 2010s Oli Pat Tomas Ului Vania Wilma Yasi Atu Book · Category · Portal · WikiProject · Commons

v t e Tropical cyclones of the 1997–98 South Pacific cyclone season 2 Lusi TD 03P 3 Martin 2 Nute 3 Osea 2 Pam 5 Susan 5 Ron 3 Katrina–Victor–Cindy 1 Tui 2 Ursula 2 Veli 2 Wes TD Unnamed TD Unnamed TD Unnamed 3 Yali 3 Zuman 1 Alan 1 Bart Book · Category · Portal · WikiProject · Commons