Cyclone Ruby

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For other storms of the same name, see List of storms named Ruby.
Tropical Cyclone Ruby
Category 2 tropical cyclone (Aus scale)
Category 1 tropical cyclone (SSHWS)
Ruby 2021-12-13 0250Z.jpg
Tropical Cyclone Ruby on 13 December
Formed10 December 2021
Dissipated17 December 2021
Highest winds10-minute sustained: 110 km/h (70 mph)
1-minute sustained: 130 km/h (80 mph)
Lowest pressure975 hPa (mbar); 28.79 inHg
FatalitiesNone
DamageUnknown
Areas affectedSolomon Islands, New Caledonia
Part of the 2021–22 Australian region and South Pacific cyclone seasons

Tropical Cyclone Ruby was a strong but short-lived tropical cyclone that impacted New Caledonia with strong winds and rainfall, after its predecessor tropical low and a nearby trough caused disruption over some parts of the Solomon Islands. The third named system of the 2021-22 Australian region cyclone season and the first cyclone of the 2021-22 South Pacific cyclone season, Ruby formed from an area of convection that was first monitored by the JTWC on 8 December in the Solomon Sea. However, the system didn't fully became a tropical low until 06:00 UTC of 10 December, where the BoM started to issue bulletins. After stalling over the area, it moved southeastwards over the Coral Sea, where it continued to develop under favorable conditions, and the system was finally upgraded into Tropical Cyclone Ruby, two days later as gale-force winds encircled its eastern portions.

Wind and rainfall alerts were placed over some islands of the Solomon Islands, due to a trough and the cyclone's predecessor. Two reservoirs, namely the Kombito and Kongulai River were closed and the public that is using the waters of the enbankments were advised to boil their waters as the rivers were contaminated with some sediments, which is linked to the rainfall from the system. Later, cyclone pre-watches were issued for the whole island of New Caledonia as Ruby slowly approached the archipelago, with warnings being further upgraded into Alert Level 2. Flights, ferry and other transportvation services were also halted as a precaution. Evacuations were also conducted to affected people. Over 2,000 residential areas lost electricity as Ruby touched down into the archipelago, with reports of trees being uprooted where in one case it impacted a house.[1] Strong winds bashed the northern part of New Caledonia, while the whole portion received heavy rainfall. No deaths were confirmed so far in the country.

Meteorological history[]

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
▲ Extratropical cyclone / Remnant low / Tropical disturbance / Monsoon depression

By 6 December, the Australian Bureau of Meteorology started to monitor the Solomon Sea and its adjoining regions for possible tropical development.[2] On the next day, the agency noted that this potential system may develop further.[3] Meanwhile, on 8 December at 06:00 UTC, the Joint Typhoon Warning Center started to track the system as "Invest 93P" while being located to 225 nautical miles (417 km; 259 mi) to the Honiara's west. At that time, the bureau noted weak convection winds around a large low-level circulation center. The sprawling disturbance is also analysed as being located in a "marginally favorable" environment by the JTWC, citing low to moderate wind shear and conducive 30–31 °C (86–88 °F) sea surface temperatures. However, the agency only gave the system a "low" chance of developing for the following 24 hours.[4] At 04:30 UTC on the next day (14:30 AEST on the previous day), the BoM designated this storm as "07U", despite the disturbance still not becoming a tropical low.[5] The JTWC further upgraded the system's chances of strengthening to "medium" by 06:00 UTC of 9 December, and to "high" by 21:30 UTC. The agency also issued a Tropical Cyclone Formation Alert (TCFA) by the latter time.[6][7]

Tropical Cyclone Ruby before it made landfall in New Caledonia on 14 December.

By the next day, the BoM noted an increase in the tropical low's organization, although its northern portion weakened. However, its southern side developed as it tracked south-southeastwards. This also indicated that the tropical low fully formed already.[8] Despite this, the system remained at its initial intensity of 25 knots (46 km/h; 29 mph), despite favorable conditions, including strong divergence from an upper-level trough over eastern Australia.[9] Its convection again degraded by 18:00 UTC, but another new chunk just formed over the low's eastern part.[10] The system also became quasi-stationary over the Coral Sea, and further became disorganized by the near-midnight.[11] The BoM also experienced difficulties in identifying the system's center by 11 December, although it slightly strengthened to 30 knots (56 km/h; 35 mph) by 06:00 UTC as per scatterometer data. The system also began to track southeastwards at this time. However, dry air were also detected in its northwest and it will gradually grow stronger because of the heat of the ocean and the heat of the air.[12][13][14]

By 18:00 UTC, the BoM noted that there are already possible gale-force winds around its convective bands, although they kept the intensity below tropical storm status. Three hours later, the JTWC upgraded the system to a tropical storm while located over 767 nautical miles (1,420 km; 883 mi) to Noumea's northwest.[15][16] Further development ensued as the tropical low slowly moved over the Coral Sea, and by 03:00 UTC, the BoM upgraded the system to a Category 1 tropical cyclone on the Australian scale and was named "Ruby" respectively as gale-force winds were detected on its eastern part.[17][18][19] By 18:00 UTC, Ruby began to continue intensify while diving south-southeastwards, becoming a Category 2 system and nearing hurricane-force intensity three hours later. The JTWC also upgraded the system to a Category 1-equivalent tropical cyclone at this time.[20][21][22] By 13:01 AEST (03:01 UTC) of 13 December, Ruby moved over the South Pacific basin, passing the responsibility of warning the system to the Fiji Meteorological Service.[23][24]

Upon moving in that region, the JTWC noted that Ruby's cloud tops had begun to warm and its convection becoming disorganized while being halfway between Australia and Vanuatu.[25] Three hours later, the system began to slightly weaken due to the combination of wind shear and dry air, according to the aforementioned agency.[26] By 20:00 UTC, Ruby began to made landfall over the northwestern portion of New Caledonia at that strength, just near severe tropical cyclone status with winds of 60 knots (110 km/h; 69 mph). This was indicated by surface and radar observations in the country. A microwave eye also appeared at this time.[27]

Preparations and impacts[]

Solomon Islands[]

Due to the cyclone's tropical low predecessor along with a trough active over the country, the Solomon Islands Meteorological Services issued a strong wind and heavy rain warnings for the archipelago.[28][29] Individuals living near rivers were also advised to prepare and take the necessary precautions, according to the meteorological agency.[30] Due to the downpour, several sediments contaminated the reservoirs at Kombito and Kongulai Rivers, forcing the water authority of the country to close them and them alerting people to boil their waters for their safety. The newspaper Solomon Star also noted that many children faced vomiting and diarrhea problems due to the incident.[31] By 10 December, the water reservoir at Kongulai was successfully restored.[32]

New Caledonia[]

Winds around 150 kilometres per hour (93 mph) and torrential rainfall were expected in New Caledonia from the storm. By 11 December, the country was placed under a cyclone pre-alert due to the brewing storm, starting at 5:00 NCST (18:00 UTC). 29 municipalities in the country were also placed under "yellow vigilance".[33][34][35] Alert Level 1 was also placed over the country's North and South Provinces and further, into Alert Level 2. Ferry service bound for the Isle of Pines, Belep and Ouaième were also halted, and Air Calédonie flights for 14 December were canceled. A school building is also requested to be an emergency shelter for possible evacuees in Houaïlou while Kouaoua's town building were used. Four areas in the country's south also offered shelter. Sport areas in Nouméa and some campuses in the University of New Caledonia were also closed.[36]

The first impacts from Ruby is felt at the North Province, where strong winds lashed the region.[36] Making landfall in the northern part of the region, Ruby is the first to do so since Cyclone Frank in 1990.[37] 678 households in Canala, Kaala-Gomen and Koumac lost electricty due to Ruby while power outages also disrupted some reservoirs in Voh. Over 2,569 lost power earlier in these areas. Poingam registered the highest wind gust retrieved from the system, at 100 knots (190 km/h; 120 mph). Touho got 140 kilometres per hour (87 mph). Trees were also downed across the country, felling power lines. A public highway is impassable in Thia due to a river being nearly-overflowed.[1][38] On a 12-hour period on 14 December, the country's west coast got its highest rainfall amount of 76.5 millimetres (3.01 in), the central registered 195.1 millimetres (7.68 in) and the east received 158.4 millimetres (6.24 in).[39] The highest rainfall amount from the system is collected from a weather station in Kouaoua, with 405 millimetres (15.9 in). 14,864 households overall lost their power supply due to Ruby. As the storm moved away from the country, all alerts were lifted and businesses reopened.[40]

See also[]

References[]

  1. ^ a b "[EN DIRECT] Ruby se renforce en descendant la côte Est" [[LIVE] Ruby strengthens as she travels down the East Coast]. LNC.nc | Les Nouvelles Calédoniennes, le Journal de Nouvelle Calédonie (in French). 2021-12-14. Archived from the original on 2021-12-14. Retrieved 2021-12-14.
  2. ^ "Tropical Cyclone Outlook for the Coral Sea Issued at 2:40 pm EST on Monday 6 December 2021 for the period until midnight EST Thursday 9 December 2021". Australian Bureau of Meteorology. 6 December 2021. Archived from the original on 7 February 2019. Retrieved 10 December 2021.
  3. ^ "Tropical Cyclone Outlook for Coral Sea Issued at 2:49 pm EST on Tuesday 7 December 2021 for the period until midnight EST Friday 10 December 2021". Australian Bureau of Meteorology. 7 December 2021. Archived from the original on 7 December 2021. Retrieved 10 December 2021.
  4. ^ "Significant Tropical Weather Advisory for the Western and South Pacific Oceans 080600Z-090600Z December 2021". United States Joint Typhoon Warning Center. 8 December 2021. Archived from the original on 2 January 2021. Retrieved 10 December 2021.
  5. ^ "Tropical Cyclone Outlook for Coral Sea Issued at 2:30 pm EST on Wednesday 8 December 2021 for the period until midnight EST Saturday 11 December 2021". Australian Bureau of Meteorology. 8 December 2021. Archived from the original on 7 February 2019. Retrieved 10 December 2021.
  6. ^ "Significant Tropical Weather Advisory for the Western and South Pacific Oceans 090600Z-100600Z December 2021". United States Joint Typhoon Warning Center. 9 December 2021. Archived from the original on 2 January 2021. Retrieved 10 December 2021.
  7. ^ "Tropical Cyclone Formation Alert (Invest 93P)". United States Joint Typhoon Warning Center. 9 December 2021. Archived from the original on 9 December 2021.
  8. ^ "Tropical Cyclone Technical Bulletin Number 1 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 10 December 2021. Archived from the original on 2 January 2021. Retrieved 11 December 2021.
  9. ^ "Tropical Cyclone Technical Bulletin Number 2 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 10 December 2021. Archived from the original on 2 January 2021. Retrieved 11 December 2021.
  10. ^ "Tropical Cyclone Technical Bulletin Number 3 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 10 December 2021. Archived from the original on 2 January 2021. Retrieved 11 December 2021.
  11. ^ "Significant Tropical Weather Advisory for the Western and South Pacific Oceans 102230Z-110600Z December 2021". United States Joint Typhoon Warning Center. 10 December 2021. Archived from the original on 2 January 2021. Retrieved 11 December 2021.
  12. ^ "Tropical Cyclone Technical Bulletin Number 4 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 11 December 2021. Archived from the original on 2 January 2021. Retrieved 12 December 2021.
  13. ^ "Tropical Cyclone Technical Bulletin Number 5 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 11 December 2021. Archived from the original on 2 January 2021. Retrieved 12 December 2021.
  14. ^ "Tropical Cyclone Technical Bulletin Number 6 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 11 December 2021. Archived from the original on 2 January 2021. Retrieved 12 December 2021.
  15. ^ "Tropical Cyclone Technical Bulletin Number 7 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 11 December 2021. Archived from the original on 2 January 2021. Retrieved 12 December 2021.
  16. ^ Tropical Storm 03P (Three) Warning No. 1 (Report). United States Joint Typhoon Warning Center. 11 December 2021. Archived from the original on 11 December 2021. Retrieved 11 December 2021.
  17. ^ "Tropical Cyclone Technical Bulletin Number 7 for Tropical Low 07U". bom.gov.au. Australian Bureau of Meteorology. 12 December 2021. Archived from the original on 2 January 2021. Retrieved 12 December 2021.
  18. ^ "Updated Tropical Cyclone Outlook for Coral Sea Issued at 1:23 pm EST on Sunday 12 December 2021 for the period until midnight EST Wednesday 15 December 2021". Australian Bureau of Meteorology. 12 December 2021. Archived from the original on 7 February 2019. Retrieved 12 December 2021.
  19. ^ "Tropical Cyclone Technical Bulletin Number 9 for Tropical Cyclone Ruby". bom.gov.au. Australian Bureau of Meteorology. 12 December 2021. Archived from the original on 2 January 2021. Retrieved 13 December 2021.
  20. ^ "Tropical Cyclone Technical Bulletin Number 11 for Tropical Cyclone Ruby". bom.gov.au. Australian Bureau of Meteorology. 12 December 2021. Archived from the original on 2 January 2021. Retrieved 13 December 2021.
  21. ^ "Tropical Cyclone Technical Bulletin Number 12 for Tropical Cyclone Ruby". bom.gov.au. Australian Bureau of Meteorology. 12 December 2021. Archived from the original on 2 January 2021. Retrieved 13 December 2021.
  22. ^ Tropical Storm 03P (Ruby) Warning No. 5 (Report). United States Joint Typhoon Warning Center. 12 December 2021. Archived from the original on 12 December 2021. Retrieved 12 December 2021.
  23. ^ "Updated Tropical Cyclone Outlook for Coral Sea Issued at 1:01 pm EST on Monday 13 December 2021 for the period until midnight EST Thursday 16 December 2021". Australian Bureau of Meteorology. 13 December 2021. Archived from the original on 7 February 2019. Retrieved 13 December 2021.
  24. ^ "Hurricane Warning 009 for Tropical Cyclone Ruby". met.gov.fj. Fiji Meteorological Service. 12 December 2021. Archived from the original on 13 December 2021. Retrieved 13 December 2021.
  25. ^ Prognostic Reasoning for Tropical Storm 03P (Ruby) Warning No. 6 (Report). United States Joint Typhoon Warning Center. 13 December 2021. Archived from the original on 13 December 2021. Retrieved 13 December 2021.
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  27. ^ Prognostic Reasoning for Tropical Storm 03P (Ruby) Warning No. 8 (Report). United States Joint Typhoon Warning Center. 13 December 2021. Archived from the original on 13 December 2021. Retrieved 13 December 2021.
  28. ^ "Strong Wind Warning Issued". Solomon Islands Times. 8 December 2021. Archived from the original on 8 December 2021. Retrieved 10 December 2021.
  29. ^ "Warning of More Heavy Rain and Possible Flooding". Solomon Islands Times. 8 December 2021. Archived from the original on 8 December 2021. Retrieved 10 December 2021.
  30. ^ "Warning of More Heavy Rain and Possible Flooding". Solomon Islands Times. 8 December 2021. Archived from the original on 8 December 2021. Retrieved 10 December 2021.
  31. ^ John Follet (8 December 2021). "Residents' advice to boil water". Solomon Star. Archived from the original on 11 December 2021. Retrieved 10 December 2021.
  32. ^ "Kongulai Water Source Restored, Kombito Remains Closed". Solomon Islands Times. 10 December 2021. Archived from the original on 10 December 2021. Retrieved 11 December 2021.
  33. ^ "Météo : une dépression tropicale se rapproche petit à petit des côtes calédoniennes" [Weather forecast: a tropical depression is gradually approaching the Caledonian coast]. Nouvelle-Calédonie la 1ère (in French). 11 December 2021. Archived from the original on 11 December 2021. Retrieved 11 December 2021.
  34. ^ "Météo : préalerte cyclonique annoncée pour dimanche matin" [Weather forecast: cyclonic early warning announced for Sunday morning]. Nouvelle-Calédonie la 1ère (in French). Archived from the original on 11 December 2021. Retrieved 11 December 2021.
  35. ^ "Désormais nommée Ruby, la dépression tropicale passe de faible à modérée" [Now named Ruby, the tropical depression goes from low to moderate]. Nouvelle-Calédonie la 1ère (in French). Archived from the original on 12 December 2021. Retrieved 12 December 2021.
  36. ^ a b "La Nouvelle-Calédonie se prépare à l'arrivée de la dépression Ruby" [New Caledonia braces for onset of Ruby Depression]. Nouvelle-Calédonie la 1ère (in French). Archived from the original on 2021-12-13. Retrieved 2021-12-13.
  37. ^ "[ACTIVITE CYCLONIQUE] #RUBY est en phase d'atterrissage sur la pointe Nord de la Grande Terre. A peu près équivalent en intensité, le dernier cyclone ayant impacté la zone est FRANK le 19 février 1999. Les dégâts avaient été très importants : routes impraticables, coupures d'eau, d'électricité et de téléphone, dommages agricoles considérables, habitations endommagées..." [[CYCLONIC ACTIVITY] #RUBY is in the landing phase on the northern tip of Grande Terre. Roughly equivalent in intensity, the last cyclone to have impacted the area was FRANK on February 19, 1999. The damage had been very significant: impassable roads, water, electricity and telephone cuts, considerable agricultural damage, damaged houses. ..]. Météo-France Nouvelle-Calédonie (in French). Archived from the original on 14 December 2021. Retrieved 14 November 2021 – via Facebook.
  38. ^ "[ACTIVITÉ CYCLONIQUE] ❗️ Attention, à proximité de #RUBY, le vent se renforce et change de direction Ainsi à Poingam, entre 05h00 et 06h00, nous sommes passés d'un vent de nord avec des rafales à 76kt, à un vent d'Ouest Sud-Ouest avec des rafales à 100kt" [[CYCLONIC ACTIVITY] ❗️ Attention, near #RUBY, the wind is strengthening and changing direction. So in Poingam, between 05:00 and 06:00, we went from a north wind with 76 kt gusts, to a southwest wind with gusts of 100 kt.]. Météo-France Nouvelle-Calédonie. 14 December 2021. Archived from the original on 14 December 2021. Retrieved 14 December 2021 – via Facebook.
  39. ^ "[ACTIVITÉ CYCLONIQUE]