Earth’s second category 5 tropical storm of 2021 is Tropical Cyclone Niran in the South Pacific Ocean. Niran is expected to affect New Caledonia as a destructive category 4 storm on Saturday.

Niran took advantage of low wind shear of 5-10 knots and warm ocean temperatures of 29 degrees Celsius (84°F) to rapidly intensity by 35 mph in just six hours on Friday, peaking as a category 5 storm with 160 mph winds and a central pressure of 917 mb at 8 am EST March 5, according to the Joint Typhoon Warning Center (JTWC). Niran’s intensity was estimated via the standard Dvorak technique, which uses infrared satellite imagery.

High wind shear is expected to gradually weaken Niran, but the cyclone is expected to be at category 4 strength as it moves along the south shore of New Caledonia’s largest island, Grande Terre, between 0 UTC and 12 UTC Saturday. Heavy damage is likely on the island, and Niran’s eyewall will pass perilously close to the capital city of Noumea (population 95,000).

Earlier this week, Niran brought heavy rains and high winds to Australia’s Queensland state, causing damage to the banana crop estimated at $138 million. Niran did not make landfall in Australia.

Figure 1. Tracks of all category 5 tropical cyclones in the South Pacific Ocean, as catalogued by NOAA’s Historical Hurricane Tracks website. The position where Tropical Cyclone Niran of 2021 achieved category 5 strength is marked with an asterisk.

South Pacific Ocean tropical cyclone history

NOAA’s hurricane history database lists 14 other tropical cyclones in the South Pacific Ocean that have achieved category 5 strength since 1988; accurate satellite data in the region dates to about 1990. The most recent Cat 5, Tropical Cyclone Harold in April 2020, caused widespread destruction in the Solomon Islands, Vanuatu, Fiji, and Tonga, killing 30 and causing more than $120 million in damage.

Three tropical cyclones are tied for being the most powerful storms on record in the South Pacific (all with 180 mph winds): Tropical Cyclone Winston (2016), Tropical Cyclone Zoe (2002), and Tropical Cyclone Monica (2006). Monica (in Australia) and Winston (in Fiji) both made landfall while at category 5 strength.

Niran is Earth’s second category 5 storm of 2021, the other being Tropical Cyclone Faraji, which reached category 5 strength on February 8 in the South Indian Ocean. It is uncommon to have two Southern Hemisphere Cat 5s so early in the year; the last time this occurred was in 2015, when Tropical Cyclone Eunice became the Southern Hemisphere’s second Cat 5 on January 30. There are only two years on record when the Southern Hemisphere has recorded as many as three category 5 storms: 2015 and 2003.

Earth averaged 5.3 category 5 storms per year between 1990 and 2020, according to ratings made by NOAA’s National Hurricane Center and the U.S. Navy’s Joint Typhoon Warning Center. The quality of the Cat 5 database is too poor and the time series of decent data on these storms too short to make definitive conclusions about how climate change may be affecting these most fearsome of storms. However, climate change is expected to make category 5 storms stronger and more numerous in coming decades.

Also see: Tropical Cyclone Faraji is first category 5 storm of 2021

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Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a...

18 replies on “Tropical Cyclone Niran rapidly intensifies to Cat 5 in South Pacific”

  1. Habana has lost it’s eye and is down to 80kts as it moved into some cooler waters. It’s expected to comeback to warmer waters and begin to restrengthen in about 36hrs.

  2. So looks like the blog has split, it will be interesting come Hurricane season I anticipate the disqus link will finally break. Anyone doing a preseason hurricane prediction pick em this year?

    1. Exactly what I showed up to check on. My backdoor link to Disqus has been out for some time now. Hopefully we have an operational home before everyone shows up in May.

  3. Niran had that look of a very strong storm in a favorable environment. Skyepony’s satellite shot below showed a robust and symmetrical vortex overstuffing the surrounding atmospheric boundaries with thick condensation, as the conditions at the surface really wanted to go up and the vector of the center of circulation was heading through a troposphere of willing space.

  4. Thanks for this information and description of the Niran situation. Hope there’s not much more damage and everyone comes through safely.

  5. Thank You for the Update Dr. on this very dangerous storm for New Caledonia; every wobble either way will make a huge difference, for any given point of these Islands, as the storm rakes across them. Have to see what happens and I hope they are prepared/evacuated from the storm surge areas.

  6. The perspective of the map is really helpful for me. It makes the South Pacific much less of a vague region and in the vicinity of Australia. Plus somewhere in there – between Auckland and Tonga are the Kermadec Islands, which have been showing up a lot in my earthquake app. Thanks.

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