With Hurricanes Harvey tearing up Austin, Irma leaving parts of Florida destroyed, and Maria bringing disastrous effects to Puerto Rico and the Caribbean, it is clear that this hurricane season has been especially catastrophic. 2017 has seen some of the most damaging storms in history and shows no signs of slowing down.

According to Bob Henson, a meteorologist for Weather Underground, this year’s hurricane season has been more active by almost every index (New York Times). Just the fact that there have been seven hurricanes so far in the season is astounding; only four other seasons have been able to match or exceed that within the past twenty years.

In addition, of the fifteen most active hurricane seasons in the past 150 or so years, ten have occurred within the past twenty years. This would make this season a little less remarkable, if it were not for the frequency and strength of the hurricanes so far. Six storms developing in a month is certainly not uncommon, but it is unusual for four of them to be either Category 4 or Category 5. In this season, four of the seven hurricanes – Harvey, Irma, Maria, and Jose – have reached Category 3 or higher, which has only occurred five times since the mid-1990s. As Henson said, “We’re running at about twice the pace of a typical season.”

So what is making this season so active? Kerry Emanuel, an atmospheric scientist who studies hurricanes at MIT, said that there are two main reasons for why this hurricane season stands out (National Geographic). In short, the tropical Atlantic is showing a greater thermal potential energy, which allows water to evaporate more rapidly. The faster the rate at which water evaporates, the higher its thermal potential. Due to these conditions, hurricanes this season have been more powerful and dangerous.

Emanuel also stated that because of a small difference in wind speed near the earth’s surface coupled with the wind speeds about ten miles up, hurricanes can grow many miles high while staying stable. For both of these reasons, atmospheric conditions are favorable for the formation of strong hurricanes.

The present conditions indeed will lead to great expense for the United States. From Harvey and Irma alone, AccuWeather estimates that the total cost is $290 billion. While 2017 might not exceed the destruction of the 2005 hurricane season, which contained the likes of hurricanes Katrina and Emily, it certainly will cause a huge amount of damage. Only time will tell if this will become a regular phenomenon, but already, this hurricane season is on its way to becoming one to be remembered.

References:

“2005 Atlantic Hurricane Season.” National Hurricane Center, USA, http://www.nhc.noaa.gov/data/tcr/index.php?season=2005&basin=atl

Gresko, Michael. “Why This Hurricane Season Has Been So Catastrophic.” National Geographic, National Geographic Society, 2 Oct. 2017, http://news.nationalgeographic.com/2017/09/hurricane-irma-harvey-season-climate-change-weather/

Astor, Maggie. “The 2017 Hurricane Season Really Is More Intense Than Normal.” The New York Times, The New York Times, 19 Sept. 2017, https://www.nytimes.com/2017/09/19/us/hurricanes-irma-harvey-maria.html