Satellite view of simultaneous Category 5 storms in the Pacific Ocean: Super Typhoon Kong-rey (left) and Hurricane Walaka (right) roil the Pacific Ocean at 10 pm EDT on 1 October 2018. Photo: NOAA / RAMMB

Dr. Jeff Masters
2 October 2018
(Weather Underground) – In a rare display of atmospheric violence, two Category 5 storms simultaneously churned across the Pacific Ocean on Tuesday morning. At 8 pm EDT Monday evening, the Central Pacific Hurricane Center elevated Hurricane Walaka a Category 5 storm with 160 mph winds, and just three hours later, the Joint Typhoon Warning Center (JTWC) also put Super Typhoon Kong-Rey at Category 5 strength. Both great storms held on to Category 5 strength through Tuesday morning. As of 11 am EDT Tuesday, both storms had weakened slightly to top-end Category 4 storms with 155 mph winds.Simultaneous Cat 5s are very rare, and this is the first time in the historical record that Cat 5s have existed simultaneously in the Northwest Pacific and Northeast Pacific. According to Dr. Phil Klotzbach of Colorado State and Jasper Deng of Wikipedia, there have been six other instances of simultaneous Category 5 storms, though:

  • July 17, 2005: Hurricane Emily in the Atlantic, Super Typhoon Haitang in the Northwest Pacific.
  • October 17-19, 1997: Super Typhoons Ivan and Joan in the Northwest Pacific
  • January 5-6, 1998: Tropical Cyclones Ron and Susan in the South Pacific
  • November 27, 1990: Super Typhoons Owen and Page in the Northwest Pacific
  • August 18, 1965: Super Typhoons Lucy and Mary in the Northwest Pacific
  • September 11, 1961, three Category 5s simultaneously!: Hurricane Carla in the Atlantic, Super Typhoons Pamela and Nancy in the Northwest Pacific […]

Global Category 5 tropical cyclones from 1990-2018, as rated by NOAA's National Hurricane Center and the U.S. Navy's Joint Typhoon Warning Center. The quality of the database rating Cat 5s is too poor and the time series of decent data on these storms is too short to make definitive conclusions about how climate change may be affecting these most powerful of storms. Climate change is expected to make the strongest storms stronger, and increase the number of Category 5 storms, so we should expect to see an increase in these mightiest of storms in the coming decades. Graphic: Weather Underground

Eight Category 5 storms so far in 2018

Kong-rey and Malaka bring the 2018 tally of Category 5 storms to eight, along with Trami, Marcus, Maria, Lane, Jebi, and Mangkhut. This puts 2018 in a tie for fifth place for most Cat 5s in a year since accurate global satellite data began in 1990. It’s possible that post-season analysis will give us another Cat 5: Hurricane Hector in the Central Pacific just missed making Category 5 status, topping out with 155 mph winds, and some of the aircraft recon data supported a higher strength.As discussed in our January post on the three Category 5 storms of 2017, that was the lowest total since 2012, and was well below the unusually high activity of 2014 – 2016, when eight or nine Category 5s appeared each year. Earth averaged 5.1 Category 5 storms per year between 1990 – 2017, according to ratings made by NOAA’s National Hurricane Center and the U.S. Navy’s Joint Typhoon Warning Center. The record number occurred in the El Niño year of 1997, which had twelve Category 5 storms–ten of them in the Northwest Pacific, where most of Earth’s Cat 5s occur. The Northwest Pacific averaged 2.9 Category 5 storms per year from 1990 – 2017, including five such storms in both 2015 and 2016. [more]

An Atmospheric Rarity: Twin Cat 5s Prowl the Pacific