|Category 4 major hurricane (SSHWS/NWS)|
|Formed||September 28, 2015|
|Dissipated||October 15, 2015|
|(Extratropical after October 8)|
1-minute sustained: 155 mph (250 km/h) |
|Lowest pressure||931 mbar (hPa); 27.49 inHg|
|Damage||$200 million (2015 USD)|
|Areas affected||The Bahamas, Bermuda, Southeastern United States (Indirect)|
|Part of the 2015 Atlantic hurricane season|
Hurricane Joaquin was a powerful category 4 hurricane, the strongest storm of the 2015 Atlantic hurricane season. It developed from a non-tropical low, which is rare for a major hurricane. It had two separate peak intensities, one of which was just under category 5 status. This storm was expected to hit the United States by many models, although this never materialized. However, an unrelated storm complex brought severe flooding to the Southeastern United States.
In mid-September 2015, an upper-level low developed over the central Atlantic. On September 27, convection began to develop over the system while it was located southwest of Bermuda. By 00:00 UTC September 28, the low had acquired sufficient organization to be declared Tropical Depression Eleven. Due to moderately strong wind shear, the depression struggled to strengthen for the next day. The depression was initially not expected to strengthen to tropical storm status; it was expected to dissipate in a few days in the western Atlantic without impacting land. However, early on September 29, after entering a more favorable environment, the depression strengthened into Tropical Storm Joaquin. Joaquin began moving more to the south-southwest than originally forecast and began to intensify. By early on September 30, Joaquin neared hurricane status, reaching hurricane intensity by 06:00 UTC that day. After reaching hurricane status, Joaquin began a period of rapid intensification. By early on October 1, while moving slowly south-southwest, Joaquin reached major hurricane intensity, eventually reaching category 4 status - making it the strongest Atlantic hurricane by pressure since Igor in 2010.
Joaquin battered the Bahamas on October 1, and resulted in the sinking of the El Faro ship and its over 30 crew members. Joaquin's initial peak intensity was as a category 4 hurricane with a minimum pressure of 931 millibars and maximum sustained winds of 140 mph. Joaquin was the first category 4 hurricane for the Bahamas in October since the 1866 season; however this event was repeated the following year with Hurricane Matthew. Joaquin weakened to a category 3 hurricane on October 2 due to an eyewall replacement cycle.
Unexpectedly, the next day while moving northeast, Joaquin acquired its secondary peak intensity with maximum sustained winds of 155 mph and a minimum pressure of 933 millibars. While it began to rapidly move northeast, rapid weakening ensued for Joaquin, and it weakened to a category 2 hurricane on October 4. Shortly afterwards, it passed near Bermuda. Joaquin then slowly weakened over the coming days, becoming a post-tropical cyclone by 00:00 UTC on October 8.
In April 2016, the World Meteorological Association (WMO) retired the name Joaquin due to its destruction in the Bahamas and sinking of El Faro. The name was replaced with Julian for the 2022 Atlantic hurricane season.