The Transcendental Outpost

Summer's on its way and NOAA warns that in this upcoming hurricane season, the North Atlantic could get as many as 13 hurricanes of category one or above. Seven of those are forecast to be major hurricanes of category three or greater. Normally, one would expect no more than seven hurricanes, total, in a season, with only three of them major. The highest number of major hurricanes in a single Atlantic season is seven, which occurred in both 2005 (the Year of Katrina) and 2020 (the year Zeta dropped a tree on my house). 

While there's no evidence climate change is producing more hurricanes, it is making more powerful ones more likely and bringing heavier rainfall.

The exact causes of individual storms are complex, but two key factors are behind the forecast. First, sea surface temperatures are much warmer than usual in the main hurricane development region in the tropical Atlantic. That often means more powerful hurricanes, because warmer waters provide more energy for storms to grow as they track westwards. Second, there is an expected switch from El Niño to La Niña weather patterns within the coming months, which helps these storms to grow more easily.

In contrast to the Atlantic, NOAA has predicted a "below-normal" hurricane season in the central Pacific region, where a move to La Niña has the opposite effect.

Tropical storms become hurricanes when they reach peak sustained wind speeds of 74 mph. 'Major' hurricanes (category three and above) are those reaching at least 111 mph. A recent study explored the need for creating a new category six level to describe the strongest hurricanes expected.

While hurricane categories only take into account wind speeds, these storms pose other major hazards, such as rainfall and coastal flooding, which are generally worsening with climate change. Warmer air can hold more moisture, increasing the intensity of rainfall. Meanwhile, storm surges - the short-term increases of sea level during hurricanes - are now happening on top of a higher base. That is because sea levels are now higher, principally due to melting glaciers and warmer seas.