Several extremely strong tropical storms in the past ten years and the likelihood of even more in the future has led some experts to suggest a new classification for massive hurricanes: Category 6.
Recent research has indicated that the impact of climate change has resulted in an increase in intensity of the most powerful tropical storms. In light of this, two climate experts have proposed the addition of a sixth category to the well-established Saffir-Simpson scale, which has been in use for over 50 years. This new category would account for storms with wind speeds reaching or exceeding 192 miles per hour (309 kilometers per hour), providing a more accurate representation of their strength.
At present, hurricanes with wind speeds of 157 mph (252 kilometers per hour) or greater are classified as Category 5. According to the researchers, the use of open-ended categories fails to adequately alert individuals to the increased risks posed by massive storms that reach speeds close to or exceeding 200 mph (322 kph).
Many experts interviewed by The Associated Press do not believe that adding another category to the hurricane scale is necessary. In fact, they argue that doing so may send the wrong message to the public, as wind speed is not the most significant factor in determining the destructive power of a hurricane. Instead, water is responsible for the majority of fatalities during these storms.
Since 2013, there have been five storms in the Pacific with wind speeds exceeding 192 mph, which would classify them in the newly defined category. Two of these storms made landfall in the Philippines. According to the study authors, as the Earth’s temperature rises, the likelihood of intense storms like these increases, including in the Gulf of Mexico where many storms that impact the United States tend to intensify.
According to lead researcher Michael Wehner, a climate scientist at Lawrence Berkeley National Laboratory, the severity of storms is being exacerbated by climate change.
According to Brian McNoldy, a hurricane researcher at the University of Miami who was not involved in the study, the increase in major hurricanes is due to warmer ocean temperatures. However, climate change does not necessarily cause an increase in the number of storms.
Occasionally, specialists have suggested a Category 6, particularly after Typhoon Haiyan achieved wind speeds of 195 mph (315 kilometers per hour) in the Pacific Ocean. However, the study stated that Haiyan “seems to be a representative example” and not a unique occurrence.
Severe wind conditions are known as hurricanes when they occur to the east of the international dateline, and as typhoons when they occur to the west. In the Indian Ocean and Australia, they are referred to as cyclones.
The five storms with winds reaching 192 mph or greater are:
In 2013, Haiyan resulted in the deaths of over 6,300 individuals in the Philippines.
In 2015, Hurricane Patricia reached a speed of 215 mph (346 kph) before it weakened and made landfall in Jalisco, Mexico.
In 2016, Typhoon Meranti had wind speeds of 195 mph and narrowly missed the Philippines and Taiwan before hitting China.
In the year 2020, Typhoon Goni caused destruction in the Philippines, claiming numerous lives with its wind speed reaching 195 mph. However, it had weakened before reaching the country.
In the year 2021, Typhoon Surigae reached wind speeds of up to 195 mph before decreasing in intensity. It narrowly passed by multiple areas in Asia and Russia.
The study’s co-author, Jim Kossin, who used to work for NOAA as a climate and hurricane researcher and is now with First Street Foundation, stated that sticking to only five categories for storms will increasingly underestimate the potential risk as these storms continue to grow in strength.
According to Kossin, Pacific storms have greater strength due to limited landmasses that do not weaken them and ample space for intensification, unlike the Gulf of Mexico and Caribbean.
According to Kossin and Wehner, although no Atlantic storm has yet reached the potential threshold of 192 mph, as the Earth continues to warm, the conditions for such a storm become increasingly favorable.
According to Wehner, the frequency of days with favorable conditions for Category 6 hurricanes in the Gulf of Mexico will increase as temperatures rise. Currently, there are approximately 10 days per year where conditions could support a Category 6 storm, but if global temperatures increase by 3 degrees Celsius (5.4 degrees Fahrenheit) from pre-industrial levels, this could potentially extend to a month. This would greatly increase the likelihood of a Category 6 hurricane occurring in the Atlantic.
Kerry Emanuel, an expert in hurricanes at MIT, commented that Wehner and Kossin provide compelling evidence for revising the current scale. However, he also noted that it is unlikely to be implemented as authorities are aware that the majority of hurricane destruction is caused by storm surge and flooding.
Jamie Rhome, the number two leader at the National Hurricane Center, stated that when issuing warnings about storms, the center aims to emphasize the specific dangers such as storm surge, wind, rainfall, tornadoes, and rip currents, instead of solely focusing on the storm category, which only conveys information about wind hazards. The highest category on the Saffir-Simpson scale, Category 5, already indicates “catastrophic damage” from wind, so it is unclear if adding another category would be necessary even if storms were to become more severe.
According to McNoldy, Craig Fugate, former Director of the Federal Emergency Management Agency, and Kristen Corbosiero, a professor of atmospheric sciences at the University of Albany, there is no need for a sixth and more powerful category for storms.
Corbosiero mentioned in an email that they may have a different opinion if a storm in the Gulf rapidly intensifies and reaches Category 6.
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