The 2011 Atlantic hurricane season was another hyperactive season, as a result of a continuing strong La Nina. This season featured a total of 20 tropical cyclones, 18 named storms, and 1 unnamed storm, 7 hurricanes, and 4 major hurricanes. This season is tied for third most active along with, 1887, 1995, 2010, and 2012. The strongest storm was Category 4 Hurricane Ophelia, that caused minimal damages.
Emily became a tropical storm in the eastern Caribbean Sea and degenerated into a tropical wave near the southwestern peninsula of Haiti. Emily then reformed in the northwestern Bahamas as a tropical storm.
Harvey was a short-lived tropical storm that made landfall with 55-kt winds in Belize and weakened as it moved across the southern Yucatan Peninsula. It re-strengthened into a tropical storm over the extreme southern portion of the Bay of Campeche before moving into southeastern Mexico, with floods causing five fatalities in that country.
Irene hit Crooked, Acklins and Long Island in the Bahamas as a category 3 hurricane (on the Saffir-Simpson Hurricane Wind Scale) but gradually weakened after crossing the Bahamas. It made landfall in North Carolina as a category 1 hurricane and caused widespread damage across a large portion of the eastern United States as it moved north-northeastward, bringing significant effects from the mid-Atlantic states through New England. The most severe impact of Irene in the northeastern United States was catastrophic inland flooding in New Jersey, Massachusetts and Vermont.
Katia was a long-track, classical Cape Verde-type hurricane that attained category 4 status (on the Saffir-Simpson Hurricane Wind Scale), but remained over the open Atlantic Ocean throughout its lifetime as a tropical cyclone. However, as a large and powerful extratropical cyclone, Katia produced hurricane-force wind gusts over much of the northern British Isles, which caused some damage and loss of life.
As part of its routine post-season review, the National Hurricane Center (NHC) occasionally identifies from new data or meteorological interpretation a previously undesignated tropical or subtropical cyclone. The NHC re-analysis of 2011 has concluded that a short-lived low that passed between Bermuda and Nova Scotia from 31 August to 3 September briefly had sufficient tropical characteristics to be considered a tropical storm.
Lee was a tropical storm that evolved into a subtropical cyclone before making landfall in southern Louisiana. Lee and its remnants contributed to heavy rainfall and extensive flooding over portions of the eastern United States.
Maria formed in the eastern Atlantic Ocean and brought tropical storm conditions to portions of the Lesser Antilles. Maria then became a category 1 hurricane (on the Saffir-Simpson Hurricane Wind Scale) as it recurved through the northwestern Atlantic before it made landfall in Newfoundland as a strong tropical storm.
Nate meandered over the Bay of Campeche for a day or so and briefly was a category 1 hurricane (on the Saffir-Simpson Hurricane Wind Scale). It then moved inland over eastern Mexico as a weak tropical storm.
Philippe was a long-lived tropical cyclone that twice became a category 1 hurricane (on the Saffir-Simpson Hurricane Wind Scale). Although it lasted for about two weeks, Philippe did not affect land.
Rina was a typical October major hurricane that formed in the western Caribbean Sea and moved toward the Yucatan Peninsula. However, it weakened significantly prior to landfall on the Yucatan Peninsula as a tropical storm and it dissipated near the Yucatan Channel.
Sean was a tropical storm that formed between the Bahamas and Bermuda. The cyclone produced a brief period of tropical-storm-force winds in Bermuda as it moved nearby.
On April 13, 2012, at the 34th Session of the World Meteorological Organization's Regional Association Hurricane Committee, the WMO retired one name, Irene from its rotating name lists. It was replaced with Irma, for the 2017 Atlantic hurricane season.