Atlantic hurricane season officially runs from June 1st to November 30th every year. however, it is not completely out of the question for tropical cyclones to form outside of that time period. In the eastern Pacific, the timeline is slightly longer, running from May 15th to November 30th. The National Hurricane Center (NHC) releases an outlook in early to mid-May with an approximation of how many tropical storms and hurricanes will develop in the upcoming season. Figure 1 is the NHC outlook from May 21, 2020 showing the prediction for the number of named storms, hurricanes, and major hurricanes during the then upcoming 2020 Atlantic hurricane season. There was a 60% chance of the season being above-normal for activity.
The earliest storm to develop in the Atlantic basin was January 3, 1938, with the formation of an unnamed Category 1 hurricane which lasted until January 6, 1938. The latest storm to develop in a calendar year was in 2005, when Tropical Storm Zeta formed in the Atlantic on December 30, 2005 and did not dissipate until January 7, 2006. It is one of two named storms, in the Atlantic basin, to exist over two calendar years.
The 2020 season, with 31 total storms, ended up exceeding scientist’s predictions and became the most active season in modern history since records began in 1851, surpassing old record of 30 storms during the 2005 season.
The most active months of hurricane season are August through October, with September 10 marking the peak. Figure 2 is a chart from the NHC showing the distribution of tropical storms and hurricanes for given dates during Atlantic hurricane season per 100 years. December through May are the least active months.
The 2020 Atlantic Hurricane season was the most active season since record keeping began in 1851, surpassing the 2005 season. In 2020, there were 31 storms that formed during the season that reached at tropical depression status. 30 of them became tropical (named) storms, and out of those 13 became hurricanes, with 6 of them intensifying into major hurricanes of category 3 status or higher. For reference, an average season has 12 named storms, six hurricanes, and three major hurricanes (category 3+), according to the National Hurricane Center (NHC).
There were also so many named storms in 2020, that the NHC ran out of names from their pre-determined 21 name list, instead resorting to using letters of the Greek Alphabet to name the remaining storms. This had only happened once, back in 2005. The last storm to form during the season, Hurricane Iota, strengthened rapidly to a Category 5 in mid-November, becoming the latest storm in history to do so.
To learn more about the 2020 Atlantic hurricane season click here.
Figure 4 is from the National Weather Service and the US Department of Commerce shows the preliminary tracks of all 31 storms (30 named storms and one depression) in the 2020 season, as well as their intensities. While some remained in the Atlantic and never threatened land, several had an impact in the Caribbean, United States and Canada. The box in the lower left shows the track of all 5 storms that made landfall in Louisiana.
Figure 5 is a chart of the 2020 Atlantic season Wikipedia page showing how the storms were distributed starting in May 2020 through November 2020. There were 11 storms in just the month of September. In fact, Wilfred, Alpha, and Beta all formed on the same day, September 18th, tying the record for the most storms formed in one day in the Atlantic.
2020 was a record-breaking year for the Atlantic hurricane season. 2020 became the year with the most tropical depressions on record at 31. 12 of the named storms made landfall in the continental United States. Of the 6 storms that intensified and made landfall as hurricanes, 5 of them made landfall in Louisiana, including Category 4 Hurricane Laura on August 27th, which became the strongest storm to make landfall in Louisiana since 1856. For comparison, according to NOAA, between 1-2 hurricanes hit the US every year, with an average of 1.62, annually.
Between 2016-2019, there were 4-5 landfalls per Atlantic hurricane season according to the National Hurricane Center. Then, the 2020 season more than doubled with 12 landfalls – a record amount for one year. The previous record for most US landfalls in a single season was 9 in 1916.
The 2020 Atlantic hurricane season was record breaking and impactful. There were 431 fatalities, and over $50 billion in damage from the 31 storms (not all storms created damages or fatalities). Many of the fatalities were due to storm surge and flooding, which is the number one killer during a hurricane or tropical storm. Many communities along the Gulf Coast of the United States, especially in Louisiana, continue to recover and rebuild from the 2020 Atlantic hurricane season.
If you are interested in learning more about landfalling hurricanes, visit the link below to look at landfall for any named storm in a NOAA database of 13,000+ storms dating back to 1842: NOAA Gov