2017 Atlantic hurricane season summary

Table of Contents:

1. Introduction
2. Season summary
3. Individual storm summaries
4. Notable records

1. Introduction

The 2017 Atlantic hurricane season was hyperactive and extremely destructive. Preliminary damage estimates for the season as a whole (USD) are running at approximately $369 billion; this total is by far the highest in the Atlantic hurricane database, originating almost entirely from the season’s three major hurricane landfalls (Harvey, Irma, and Maria). For the first time since 2005, the United States was hit by a major hurricane (Category 3 or higher on the Saffir-Simpson Hurricane Wind Scale), with Harvey and Irma both striking the coast as major hurricanes.

2. Season summary

The 2017 Atlantic hurricane season was exceptionally active. 17 named storms occurred compared to a long-term average of 12; even if we take the 1995-2016 average of 15, these totals were still above average. In terms of named storms, only 6 seasons since the active era in 1995 have matched or exceeded this total, and only two prior to the satellite era. 10 of these cyclones became hurricanes, with 6 becoming major hurricanes (Category 3 or higher on the Saffir-Simpson Hurricane Wind Scale, or 1-minute average sustained winds of greater than 110 mph). These numbers are considerably above the long-term average of 7, with the number of major hurricanes especially notable, and boasting the highest count since 2005, when 7 occurred. In addition, the 10 hurricanes occurred consecutively (Franklin to Ophelia), a feat that has not happened since 1893.

An abundance of land areas were affected by tropical cyclones in 2017, with the United States, the Bahamas and the Caribbean affected the most by this year’s storms. Harvey was the first major hurricane landfall in the United States since Wilma in 2005, and Irma was the first major hurricane to make landfall in Florida since Wilma as well. The Caribbean was struck by two Category 5 hurricanes; Irma and Maria. Irma was the first Category 5 hurricane to strike Cuba since 1932, and Maria was an especially intense hurricane for the islands of the northeastern Caribbean, attaining Category 5 status and winds of 150 kt; in the satellite era, only Hugo (1989) and Irma (2017) were of comparable strength to Maria in this area. In addition, the southern and western Bahamas were severely affected by Irma. In addition, Mexico and Central America were impacted by Franklin, Katia and Nate, respectively. Collectively, the tropical cyclones of 2017 caused an estimated 882 fatalities (Wikipedia).

In terms of Accumulated Cyclone Energy (ACE), 2017’s 223 makes it the most active since 2005, and places the 2017 season within the top 10 most active seasons since 1851.  More than the impressive amount of tropical cyclone activity in 2017, the exceptionally high ACE index – over 3 times the normal – adequately displays the intense level of hurricane activity in the Atlantic this year. Irma alone attained an ACE of 67 (rounded), and this value is behind only the 1899 San Ciriaco hurricane and Ivan in 2004.

3. Individual storm summaries

1a. Tropical Storm Arlene
2a. Tropical Storm Bret
3a. Tropical Storm Cindy
4a. Tropical Storm Don
5a. Tropical Storm Emily
6a. Hurricane Franklin
7a. Hurricane Gert
8a. Hurricane Harvey
9a. Hurricane Irma
10a. Hurricane Jose
11a. Hurricane Katia
12a. Hurricane Lee
13a. Hurricane Maria
14a. Hurricane Nate
15a. Hurricane Ophelia
16a. Tropical Storm Philippe
17a. Tropical Storm Rina

1a. Tropical Storm Arlene (19 – 21 April)

Arlene developed from a non-tropical low pressure system that had occluded over the central Atlantic. The associated non-tropical surface low slowly shed its frontal characteristics as it moved east-northeastward to a position a few hundred miles west-southwest of the Azores on 19 April, becoming a subtropical depression on this day. Initial strengthening was slow, but the cyclone made the transition to a tropical storm on 20 April. Arlene moved in a counter-clockwise direction along the eastern and northern periphery of a larger extratropical low to its west, ultimately dissipating within this new cyclone on 21 April. Arlene had no impacts to land.