2015 Atlantic hurricane season

Season overview

2015 was the third below-average Atlantic season in a row. Twelve tropical cyclones were tracked, of which 11 reached tropical storm strength; the twelfth, Tropical Depression Nine, never did. The National Hurricane Center's season summary, which counts from its own best track, lists the same 11 named storms, 4 hurricanes and 2 major hurricanes that the site's archive gives, and an accumulated cyclone energy of 62.7 sat well below the 1981 to 2010 median of about 92.

The main brake on the season was a strong El Niño, which enhanced westerly wind shear over the basin, while the large-scale circulation favoured dry, sinking air over the low latitudes west of 40°W. Forecasters had seen this coming: almost every major seasonal outlook, drawing on the developing El Niño and cooler than average tropical Atlantic waters, called for a below-normal or near-normal year, and the outcome broadly matched those predictions.

How the season unfolded

The season started before its official 1 June opening. Ana formed from a non-tropical low off the Carolinas on 8 May as a subtropical storm and became fully tropical on 9 May, the first tropical-stage observation in the archive. Bill followed in the northwestern Gulf of Mexico in mid-June, and Claudette, the only system of July, spun up quickly off the North Carolina coast and lasted barely two days as a tropical storm.

No storms formed in the first half of August, and the season's first hurricane did not arrive until Danny strengthened on 20 August. From then on the pace picked up. Erika and Fred followed within a week, and September brought five systems: Grace, Henri, Tropical Depression Nine, Ida and Joaquin. Most of these were short-lived or weak, struggling against shear and dry air in the open Atlantic.

Joaquin carried activity into October, though no new storm formed that month. The season closed with Kate, which formed just north of the Turks and Caicos Islands on 8 November, became a hurricane over the open Atlantic on 11 November and lost its tropical characteristics the same day, the last tropical-stage observation of the year.

Strongest storms

Hurricane Joaquin was the season's strongest, deepest and longest-lived storm. It grew from a non-tropical low northeast of the Bahamas in late September and, over sea temperatures that were about 1.1°C above normal and the warmest on record for the period, went through a 60-hour spell of rapid intensification. It became a major hurricane on 1 October while stalling in a clockwise hairpin loop over the southeastern and central Bahamas, and its central pressure bottomed out at 931 hPa on 2 October.

As a trough over the eastern United States pulled Joaquin northeastward away from the islands, the hurricane strengthened again and reached its peak of 135 kt on 3 October, just short of Category 5. Shear soon eroded its eyewall, and it passed about 60 nautical miles west-northwest of Bermuda on 5 October before turning out to sea. The National Hurricane Center ranks Joaquin as the strongest Atlantic hurricane of non-tropical origin in the satellite era.

The season's other major hurricane was Danny, a compact Cape Verde storm that fought the dry Saharan Air Layer for days before rapidly intensifying to a 110 kt Category 3 hurricane on 21 August as a small eye formed. Its burst of strength was brief: dry air and shear took it apart before it reached the Leeward Islands, where it arrived as a depression and degenerated into a tropical wave. The remaining two hurricanes, Fred and Kate, both peaked at Category 1 with 75 kt winds.

Landfalls and impacts

Joaquin brought the season's most severe damage. Its eyewall and storm surge swept Crooked Island, Acklins, Long Island, Rum Cay and San Salvador for more than two days; about 70 percent of Crooked Island flooded under at least five feet of water, and floodwaters lingered on Long Island a week later. Damage in the Bahamas was later put at about US$200 million (2015 dollars). Offshore, the US cargo ship El Faro lost propulsion near Crooked Island and sank with all 33 crew, and a fisherman drowned off Haiti, for 34 direct deaths in the National Hurricane Center's count, all at sea.

Tropical Storm Erika never exceeded 45 kt in the archive, but its torrential rain on Dominica in late August set off catastrophic flooding and mudslides. The National Hurricane Center attributes 30 direct deaths to Erika, all on Dominica, with press estimates of damage on the island ranging up to US$500 million (2015 dollars). Farther west, Erika's winds and rain left about 250,000 people without power in Puerto Rico, where agricultural losses reached about US$17.4 million (2015 dollars).

Fred took an unusual northwestward path straight off the African coast and moved through Cabo Verde as a hurricane on 31 August, the first hurricane to do so since 1892, prompting the islands' first ever hurricane warning. The National Hurricane Center counts nine direct deaths: seven crew lost when a fishing boat sank off Guinea-Bissau in Fred's high seas, and two Cabo Verde fishermen who never returned to port. Media reports put damage in Cabo Verde at about US$1 million (2015 dollars), with Boa Vista hit hardest.

The United States took two tropical storm landfalls. Ana came ashore near North Myrtle Beach, South Carolina, on 10 May, the earliest US-landfalling tropical cyclone on record, causing beach erosion and one direct death from rip currents in North Carolina. Bill made landfall on Matagorda Island, Texas, on 16 June and dumped heavy rain on ground already soaked by record May flooding in Texas and Oklahoma; it caused three direct flooding deaths in the United States, and its precursor's rains killed two people in Honduras and two in Guatemala. US damage from Bill was estimated at at least US$100 million (2015 dollars).

Retired names and records

In April 2016 the World Meteorological Organization retired Erika and Joaquin, replacing them with Elsa and Julian for the 2021 list. Erika became only the second storm of the satellite era to be retired without reaching hurricane strength, after Tropical Storm Allison. The season also stretched the United States' run without a major hurricane landfall to ten years, dating back to Hurricane Wilma in 2005.