2011 Atlantic hurricane season
The 2011 Atlantic hurricane season was the second in a group of three very active Atlantic hurricane seasons, each with 19 named storms, only behind 1887, 1995, 2010, and 2012. The above-average activity was mostly due to a La Niña that persisted during the previous year. Of the season's 19 tropical storms, only seven strengthened into hurricanes, and four of those became major hurricanes: Irene, Katia, Ophelia, and Rina. The season officially began on June 1 and ended on November 30, dates which conventionally delimit the period during each year in which most tropical cyclones develop in the Atlantic Ocean. However, the first tropical storm of the season, Arlene, did not develop until nearly a month later. The final system, Tropical Storm Sean, dissipated over the open Atlantic on November 11.
Due to the presence of a La Niña in the Pacific Ocean, many pre-season forecasts called for an above-average hurricane season. In Colorado State University (CSU)'s spring outlook, the organization called for 16 named storms and 9 hurricanes, of which 4 would intensify further into major hurricanes. On May 19, 2011, the National Oceanic and Atmospheric Administration (NOAA) issued their pre-season forecast, predicting 12–18 named storms, 6–10 hurricanes, and 3–6 major hurricanes. Following a quick start to the season, NOAA subsequently increased their outlook to 14–19 named storms, 7–10 hurricanes, and 3–5 major hurricanes on August 4; CSU made no changes to the number of cyclones forecast throughout the year.
Many tropical cyclones affected land during the 2011 season; most impacts, however, did not result in a significant loss of life or property. On June 29, Arlene made landfall in Mexico near Cabo Rojo, Veracruz, causing over $223 million (2011 USD) damage and killing 22 people.[nb 1] Tropical Storm Harvey moved into the coastline of Central America in mid-August, and three deaths were reported as a result. During the month of September, Tropical Storm Lee and Hurricane Nate moved into the central United States Gulf Coast and central Mexico, respectively; the former led to 18 deaths, and the latter caused 5 fatalities. As an extratropical cyclone, Lee caused significant damage in the form of flooding across the Northeast United States, especially in New York and Pennsylvania. The deadliest and most destructive cyclone of the season developed east of the Lesser Antilles on August 21. Hurricane Irene caused significant impact across some of the Caribbean Islands and United States Eastern Seaboard, leaving about $14.2 billion in damage and resulting in the name's retirement. Overall, the season resulted in 112 deaths and nearly $17.4 billion in damage.
Duration
June 28 – July 1
July 17 – July 22
July 20 – July 23
July 27 – July 30
August 2 – August 7
August 12 – August 13
August 13 – August 16
August 19 – August 22
August 21 – August 28
August 25 – August 26
August 27 – August 29
August 29 – September 10
September 1 – September 3
September 2 – September 5
September 6 – September 16
September 7 – September 11
September 20 – October 3
September 24 – October 8
October 23 – October 28
November 8 – November 11