The Cook Islands can be divided into two groups: the Southern Cook Islands and the Northern Cook Islands. The country is located in Oceania, in the South Pacific Ocean, about halfway between Hawaii and New Zealand.
Severe Tropical Cyclone Heta was a Category 5 tropical cyclone that caused moderate damage to the islands of Tonga, Niue, and American Samoa during late December 2003 and early January 2004. Heta formed on December 25, 2003; it reached a maximum intensity of 260 km/h (160 mph) and an estimated pressure of 915 hPa before dissipating on January 11, 2004. It was the first named tropical cyclone to form during the 2003–04 South Pacific cyclone season.
Severe Tropical Cyclone Olaf was the sixth cyclone to form in the Southwest Pacific Ocean during the 2004–05 South Pacific cyclone season. Olaf was also one of three simultaneous cyclones to form during the 2004–05 season, forming 21 hours after Cyclone Nancy formed to the east. A powerful Category 5 cyclone, Olaf stuck American Samoa causing heavy damage although exact estimates are unknown. Despite the damage, there were no reported deaths or injuries from the cyclone. Olaf was third South Pacific cyclone to hit the Cook Islands during the 2004–05 season, and Cyclone Percy would later affect the already devastated archipelago less than 2 weeks later.
Severe Tropical Cyclone Percy was an extremely powerful tropical cyclone which was the third and last Category 5 cyclone to form in the 2004–05 South Pacific cyclone season. The seventh named storm and the fourth and final severe tropical cyclone to form during the 2004–05 South Pacific cyclone season. Percy originated as a tropical disturbance on February 23. Over the course of the next few days, the system organized while moving east-southeastward, before intensifying into a Category 1 tropical cyclone on the Australian region scale on February 26. The system quickly intensified, reaching Category 4 status later that day. On the next day, Percy was steered southward by a blocking ridge of high pressure, while stretched out the structure of the storm into an elliptical shape, weakening it back to Category 3 status. Afterward, the storm rapidly reintensified, reaching its peak intensity as a Category 5 tropical cyclone on March 2. Afterward, Percy encountered increasing wind shear and weakened once again, turning southeastward on the next day. On March 5, Percy transitioned into an extratropical storm, before dissipating soon afterward.
The 1998–99 South Pacific cyclone season was a near average South Pacific tropical cyclone season, with 8 tropical cyclones occurring within the South Pacific Ocean basin between 160°E and 120°W. Despite the season starting on November 1, the first tropical system of the season did not form until December 1, while the final disturbance of the season dissipated on May 27, 1999. During the season the most intense tropical cyclone was Severe Tropical Cyclone Cora, which had a minimum pressure of 930 hPa (27.46 inHg). After the season had ended the names Cora and Dani were retired from the naming lists, after they had caused significant impacts to South Pacific islands.
The 2009–10 South Pacific cyclone season began on December 3, 2009 with the formation of Tropical Disturbance 01F, 32 days after the cyclone season had officially begun on November 1, 2009. The season ended on April 30, 2010. These dates conventionally delimit the period of each year when most tropical cyclones form in the southern Pacific Ocean east of 160°E. Additionally, the regional tropical cyclone operational plan defines a tropical cyclone year separately from a tropical cyclone season; the "tropical cyclone year" began on July 1, 2009 and ended on June 30, 2010. Tropical cyclones between 160°E and 120°W and north of 25°S are monitored by the Fiji Meteorological Service. Those that move south of 25°S are monitored by the Tropical Cyclone Warning Centre in Wellington, New Zealand. The first tropical disturbance of the season formed on December 3, about 1015 km (700 mi) to the north of Suva, Fiji and later intensified into Tropical Cyclone Mick. The last system, 15F, dissipated on April 5 of the following year.
Severe Tropical Cyclone Nancy was the second in a series of four severe tropical cyclones to impact the Cook Islands during February 2005. Forming out of an area of low pressure on February 10, Nancy quickly organized into a small, but intense, cyclone. By February 14, the storm explosively intensified into a Category 4 severe tropical cyclone with winds peaking at 175 km/h (109 mph) 10-minute winds) and a minimum barometric pressure of 935 hPa (mbar). Over the following day, increasing wind shear rapidly weakened the cyclone and by February 17, it transitioned into an extratropical cyclone shortly before being absorbed by Cyclone Olaf.
Severe Tropical Cyclone Keli was the first recorded post-season tropical cyclone to form in June within the South Pacific Ocean. The system formed on June 7, 1997, about 460 kilometers (285 mi) to the north of Tokelau. The depression gradually developed over the next few days while moving southwestward. It was designated as Tropical Cyclone Keli early the next day. Cyclone Keli intensified, slowly reaching its 10-minute peak wind speeds of 150 km/h (90 mph), which made it a Category 3 severe tropical cyclone on the Australian Tropical Cyclone Intensity Scale. As it came under the influence of strong mid latitude westerlies and moved into an area of strong vertical wind shear, the cyclone started to weaken and was declared extratropical on June 15.
The 1989–90 Australian region cyclone season was an above average tropical cyclone season. It was also an event in the ongoing cycle of tropical cyclone formation. It ran from 1 November 1989 to 30 April 1990. The regional tropical cyclone operational plan also defines a tropical cyclone year separately from a tropical cyclone season, and the "tropical cyclone year" ran from 1 July 1989 to 30 June 1990.
The 1989–90 South Pacific cyclone season was a below-average season with only five tropical cyclones occurring within the South Pacific to the east of 160°E. The season officially ran from November 1, 1989, to April 30, 1990, with the first disturbance of the season forming on November 8 and the last disturbance dissipating on March 19. This is the period of the year when most tropical cyclones form within the South Pacific Ocean.
Tropical Cyclone Trina was a weak but destructive tropical cyclone in late 2001 which caused some of the worst flooding in the South Pacific island of Mangaia, Cook Islands, in nearly 50 years. Forming out of an upper-level low pressure system on November 29 near the island of Rarotonga, or roughly 1,470 mi (2,365 km) southeast of Fiji, Trina remained practically stationary as it meandered in the same general area for over a week. Due to unfavorable conditions for tropical cyclogenesis, the storm struggled to develop significant convection, preventing it from intensifying beyond 65 km/h (40 mph). After finally succumbing to wind shear on December 2, the system weakened to a tropical depression near Mangaia and dissipated several days later.
Severe Tropical Cyclone Val was considered to be the worst tropical cyclone to affect the Samoan Islands since the 1889 Apia cyclone. The system was first identified during the opening days of December 1991, as a small circulation, within the Intertropical Convergence Zone to the north of Tokelau. Over the next few days, the system moved westwards towards Rotuma and Tuvalu and gradually developed further, before it was named Val on December 5, after it had become a category 1 tropical cyclone on the Australian tropical cyclone intensity scale. The system subsequently continued to intensify as it moved towards the Samoan Islands and peaked as a category 4 severe tropical cyclone, as it made landfall on the island of Savaii on December 6. After Val had passed over the island, weakening upper-level winds caused the system to slow down before it made a sharp clockwise loop which almost brought it over Savaii for a second time.
Severe Tropical Cyclone Pat was a small but strong tropical cyclone that passed directly over Aitutaki, Cook Islands, in southern Pacific Ocean on February 10, 2010. Part of a series of storms to impact the group of islands early that year, Pat was first identified as a tropical depression on February 6 well to the northeast of the Samoan Islands. The storm steadily organized as it moved generally southeast, becoming a tropical cyclone on February 8. Turning to the south, intensification began in earnest and the system acquired hurricane-force winds within 48 hours of being named. The 445 km (275 mi) wide system displayed annular characteristics and a 19 km (12 mi) wide eye. Pat reached its peak strength early on February 10 as a severe tropical cyclone with winds of 140 km/h (85 mph) and a barometric pressure of 960 mbar. Hours later it struck Aitutaki, producing gusts in excess of 185 km/h (115 mph) on the island. Hostile wind shear then prompted rapid weakening of the cyclone. The system degraded below gale-intensity on February 11, just 24 hours after it peaked, and was last noted early on February 12.
The 2019–20 Australian region cyclone season was a below average tropical cyclone season for the waters surrounding Australia between longitudes 90°E and 160°E. The season officially began on 1 November 2019 and ended on 30 April 2020; however, tropical cyclones can form at any time of year, as evidenced by Tropical Cyclone Mangga during May 2020. As such, any system existing between 1 July 2019 and 30 June 2020 would count towards the season total. The season featured the region's second-latest start on record, with the formation of the first tropical low only occurring on 4 January 2020. A total of eight tropical cyclones formed during the season, which represents the region's least active season since the 2016–17 season. Three systems intensified further into severe tropical cyclones, and three systems made landfall within the region at tropical cyclone intensity. A total of 28 fatalities were caused, either directly or indirectly, as a result of impacts from the season's systems. Cyclone Ferdinand was the strongest of the season reaching Category 4 in late February 2020. However, it was the second-strongest storm, Cyclone Damien, that was the most damaging. Damien was the strongest tropical cyclone to strike Western Australia's Pilbara Region since Cyclone Christine in 2013, making landfall directly over the town of Dampier.
Severe Tropical Cyclone Martin was the deadliest tropical cyclone of the 1997–98 South Pacific cyclone season. The system was first noted as a weak tropical disturbance on October 27, to the north of the Northern Cook Islands. Over the next few days atmospheric convection surrounding the system remained disorganized, as it moved towards the southwest and was affected by strong upper-level north-easterly winds and moderate to strong vertical wind shear. The system was subsequently named Martin during October 31, after it had rapidly developed further and shown a marked improvement organization.
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.
Severe Tropical Cyclone Sina was the only named tropical cyclone to develop within the South Pacific basin during the 1990–91 season. The system was first noted as a shallow depression within the South Pacific Convergence Zone to the west of Wallis Island. Over the next three days the system moved towards the west-northwest, before it was named Sina during November 24, after it had developed into a tropical cyclone. Over the next couple of days the system intensified further and developed an eye feature as it erratically moved towards Fiji. Sina subsequently peaked in intensity during November 26, before the system passed through the Fijian Islands over the next two days as it started to gradually weaken. Sina subsequently passed just to the north of Tongatapu in Tonga during November 29, before it passed about 160 km (100 mi) to the south of Niue and near the Southern Cook Islands during the next day. The system subsequently rapidly weakened and became an extratropical cyclone during December 1, before they were absorbed by an advancing trough of low pressure near 50°S on December 4.
Severe Tropical Storm Zelda was the last tropical cyclone of the 1991 Pacific typhoon season; it struck the Marshall Islands on November 28. The area of low pressure that eventually became Zelda formed near the International Date Line, and strengthened into a tropical depression on November 27. The Joint Typhoon Warning Center (JTWC) reported that the depression had reached tropical storm intensity near the Marshall Islands on November 28, thus naming it Zelda. On November 29, the storm quickly strengthened to 65 knots according to the JTWC, equivalent to a Category 1 typhoon on the Saffir–Simpson hurricane wind scale. It reached a peak of 80 kn according to the JTWC, and 60 kn according to the Japanese Meteorological Agency (JMA), with a barometric pressure of 975 hectopascals (28.8 inHg). Zelda weakened into a tropical storm on December 2, and then a tropical depression two days later. The JTWC discontinued warnings late on December 4, while the JMA declared the storm to be extratropical the next day and continued to track until it crossed the International Date Line again on December 7.
Severe Tropical Cyclone Tino was a tropical cyclone which itself and an associated convergence zone caused significant damage across ten island nations in the South Pacific Ocean during January 2020. First noted as a tropical disturbance during January 11, to the southwest of Honiara in the Solomon Islands, the system gradually developed over the next few days as it moved eastwards in between the Solomon Islands and Vanuatu prior to being named Tino as it approached Fiji during January 16. Continuing to track south-eastward, Tino continued strengthening as it passed near Fiji, bringing copious amounts of rainfall to the area. Whilst losing latitude, the system continued to strengthen and peaked as a category 3 tropical cyclone on January 17, with signs of an eye forming. Shortly after peak intensity, Tino was impacted by high wind shear and decreasing sea surface temperatures, triggering a weakening trend. Tino moved out of the tropics shortly thereafter and became an extratropical cyclone during January 19.
Legislative Council elections were held in the Cook Islands in 1947, the first after the establishment of the new legislature.
