Cyclone Susan

Severe Tropical Cyclone Susan

Category 5 cyclone (Australian scale) Category 5 Tropical cyclone (SSHWS)
Cyclone Susan near its peak intensity on January 5, just before it re-curves away from Vanuatu.
Formed	December 20, 1997
Dissipated	January 10, 1998
Highest winds	10-minute sustained: 230 km/h (145 mph) 1-minute sustained: 260 km/h (160 mph)
Lowest pressure	900 mbar (hPa); 26.58 inHg
Fatalities	1
Damage	> $100,000 (1998 USD)
Areas affected	Vanuatu, Fiji, New Zealand
Part of the 1997–98 South Pacific cyclone season

Severe Tropical Cyclone Susan was one of the most intense tropical cyclones on record within the South Pacific basin, which was first noted on December 20, 1997, as a weak tropical disturbance located to the north of American Samoa. Over the next 12 days, the disturbance remained weak while it gradually moved towards the southwest before it started to rapidly develop on January 2, 1998 while it was located near the Fijian dependency of Rotuma. The disturbance was declared a tropical cyclone later that day, but was not named Susan until the next day, after it had intensified into a category 2 tropical cyclone on the Australian Scale. Over the next few days, Susan moved towards the southwest and continued to intensify before it reached its peak intensities as a category five tropical cyclone during January 5 while it was located about 400 km (250 mi) to the northwest of Vanuatu's capital city Port Vila.

At this stage as the cyclone was moving towards the southwest it posed a severe threat to Vanuatu however, during that day Susan recurved towards the southeast and subsequently spared Vanuatu a direct hit. After sparing Vanuatu a direct hit, Susan started to accelerate towards the southeast and while starting to weaken significantly passed close enough to Fiji during January 7 and 8 to cause gale force winds in Fiji's southern and western islands. While continuing to move towards the southeast, Susan started to interact with Severe Tropical Cyclone Ron during January 8 before it absorbed Ron by 0600 UTC the next day and starting to transition into an extratropical cyclone. The extratropical remnants of the combined systems were then monitored for another day until they were last noted on January 10, bringing an unseasonable cold snap to New Zealand. Despite sparing Vanuatu and Fiji direct hits, heavy rain and gale force winds associated with Susan were reported to have caused minor damage to several Vanuatuan and Fijian islands. These islands included Viti Levu where a possible tornado destroyed the roof of a shopping centre and the Vanuatuan island of Ambrym, where a woman died after being hit by a falling coconut tree, while gathering supplies to secure her house with.

Meteorological History

On December 20, the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi), started to monitor a weak tropical disturbance that was located about 915 km (570 mi), to the northwest of Pago-Pago in American Samoa.^[1][2] Over the next 12 days, the system remained weak and disorganized, while gradually moving towards the west-southwest.^[3][4] After 0000 UTC on January 2, the disturbance started to rapidly develop further, in an area of weak vertical windshear while it was located near the Fijian dependency of Rotuma.^[3][5] Later that day, RSMC Nadi reported that the disturbance had intensified into a category one tropical cyclone on the Australian tropical cyclone intensity scale, however they did not name the cyclone; Susan, until 0400 UTC on January 3.^[4][6] Early on January 3, the USM's Joint Typhoon Warning Center (JTWC) designated the cyclone as Tropical Cyclone 11P after it had become equivalent to a tropical storm with 1-minute wind speeds of 65 km/h (40 mph).^[7] During that day, the system continued to rapidly develop further with RSMC Nadi reporting at 1200 UTC that it had become a category two tropical cyclone, before they reported twelve hours later that Susan had become a category 3 severe tropical cyclone with 10-minute sustained windspeeds of 120 km/h (75 mph).^[8] During January 4, Susan continued to rapidly intensify with the JTWC reporting that Susan had become equivalent to a category 1 hurricane on the Saffir-Simpson Hurricane Scale as convection surrounding the system organized further and developed an eye feature.^[2][9]

Cyclone Susan absorbing Cyclone Ron

As the subtropical ridge of high pressure that was located to the south of the cyclone started to weaken, which meant that Susan started to move further towards the southwest.^[10] RSMC Nadi then reported at 0000 UTC on January 5, that the system had become a category 5 severe tropical cyclone with 10-minute sustained wind speeds of 140 mph (220 km/h), before reporting 6 hours later that Susan had reached its peak 10-minute sustained wind speeds of 145 mph (225 km/h) and a peak pressure of 900 hPa (26.58 inHg).^[11] Around this time RSMC Nadi reported that the system might of developed a double eye feature while the JTWC reported that Susan had peaked with 1-minute wind speeds of 260 km/h (160 mph) equivalent to a weak category five hurricane on the SSHS.^[2][10] As the system reached its peak intensity, Susan was moving towards the southwest and as a result, it "posed a severe threat to Vanuatu," however during that afternoon, Susan recurved towards the southeast "just in time to spare Vanuatu, a direct hit.”^[1] After turning away from Vanuatu, Susan accelerated towards the southeast while remaining near or at its peak intensities, before starting to weaken significantly during January 7.^[11] RSMC Nadi then reported early the next day, that Susan had weakened into a category 4 severe tropical cyclone while it was located about 435 km (270 mi), to the southeast of Nadi, Fiji, which was close enough for the system to produce gale force winds in several southern and western Fijian Islands.^[3][8] By 0000 UTC on January 9, Susan had completely absorbed Cyclone Ron, before the final advisories on the combined system, were released later that day as it lost its tropical characteristics and became extratropical.^[1][12] 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.^[11][13]

Intensity

According to RSMC Nadi, Susan had peak 10-minute sustained windspeeds of 230 km/h (145 mph) which made it a category five severe tropical cyclone on the Australian tropical cyclone intensity scale.^[8][14] RSMC Nadi also estimated that Susan had an estimated minimum pressure of 900 hPa (26.58 inHg), which made it one of the two most intense tropical cyclones on record in the Southern Pacific.^[8][15] This record was subsequently broken in 2002, when Severe Tropical Cyclone Zoe had an estimated minimum pressure of 890 hPa (26.28 inHg) and became the most intense tropical cyclone on record in the southern Pacific and Australian basins.^[16]

Preparations and impact

Cyclone Susan caused 1 death and at least 7005100000000000000US$100 thousand worth of damage, when it affected Vanuatu and Fiji during January 1998.^[6] Due to the impact of this storm, the name Susan was retired from the lists of tropical cyclone names.^[17]

Vanuatu

On January 5, the Vanuatu National Disaster Management Council issued various tropical cyclone alerts for various islands to warn residents about the approaching cyclone, which included a red alert for the Maewo, Pentecost and Ambae islands.^[18][19] Because of the upcoming cyclone Vanuatu's national radio extended its programming to run throughout the night of January 5–6, while Vanuatu's domestic airline Vanair closed its airfields in the northern islands and cancelled all of its flights except for several direct flights between Santo Island and Port Vila the capital city of Vanuatu.^[18] All ships and small boats were advised to seek refuge due to the high seas and swells that were expected from Susan.^[18][20] However during the afternoon of January 7, Susan recurved towards the southeast and the Fijian islands "just in time to spare Vanuatu, a direct hit.^[1] Despite being spared a direct hit, heavy rain and gale force winds were reported to have caused minor damage to several Vanuatuan Islands, including on Ambrym Island, where a woman died after being hit by a falling coconut tree, while gathering supplies to secure her house with.^[3][21][22] After the alerts were cancelled on January 7, by the National Disaster Management Council, most shops and government buildings on Efate island kept their shutters up because Cyclone Katrina was predicted to affect the archipelago within a few days.^[19]

Fiji

Late on January 6, RSMC Nadi issued a tropical cyclone alert for Fiji, while Susan was located about 600 km (375 mi) to the west of Nadi, Fiji.^[6] The alert stated that Susan, was expected to pass as close as 300 km (185 mi) to the southwest of Viti Levu during the next day.^[6] It also warned that there was a chance that the cyclone would curve more towards the east-southeast and bring gale force or stronger winds over Fiji.^[6] Early the next day as squally strong north to north-easterly winds were starting to affect Fiji, RSMC Nadi upgraded the alert to a gale warning for Vatulele, Kadavu, western and south-western Viti Levu and the Yasawa and Mamanuca island groups.^[6]

On January 7 and 8, Susan passed close enough to Fiji, to cause some minor coastal damage to several southern and western Fijian islands, including on the main island of Viti Levu.^[3] The cyclone also brought with it some beneficial rainfall which helped to ease the drought conditions that were present in Fiji.^[19] However, gale force winds, high seas, a heavy swell and storm surge inundated Bequ Island and a village on Kadavu Island, while partly destroying beach-fronts, roads, jetties and bridges within the archipelago.^[3] Within Lautoka several shops, power lines, a bus station and the roof of a shopping complex were damaged after what was believed to be either a tornado or tornadic winds developed in one of Susan's rainbands as it crossed the shoreline.^[1][6][23] Firemen and linesmen from the Fiji Electricity Authority were called in to assist police to clear downed power wires.^[23]

See also

• Cyclone Ron
• 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

• A "fly-thru" of Cyclone Susan - created by NASA's Tropical Rainfall Measuring Mission

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