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1965 Atlantic hurricane season

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Hurricane Betsy was the strongest and most devastating storm of the season. Extensive damage from Betsy was reported in the Bahamas, Florida, and Louisiana, particularly the New Orleans area. It was the first hurricane in the history of the United States to result in at least $1 billion (1965 USD) in losses. Hurricane Carol meandered in the eastern Atlantic for over two weeks from mid-September to very early October. Impact on land from Carol was minimal. In late September, Tropical Storm Debbie developed in the northwestern Caribbean and moved slowly across the region, before later reaching the Gulf of Mexico. The storm dissipated just offshore of Louisiana, which resulted in only minor impact along the Gulf Coast of the United States. The final tropical cyclone, Hurricane Elena, formed on October 12. Elena remained at sea for nearly a week and caused no damage on land. Collectively, the storms of the 1965 Atlantic hurricane season caused 76 fatalities and $1.68 billion in damage, almost entirely due to Hurricane Betsy.

Season summary

This was the first Atlantic hurricane season to start on June 1 and end on November 30, which is the modern-day season bounds. A total of 13 tropical depressions formed. Ten of those tropical depression intensified into a tropical storm, which was just slightly below the National Oceanic and Atmospheric Administration's 1950–2005 average of 11. Four of those tropical storms attained hurricane status, slightly below the average of six. One hurricane intensified into a major hurricane, which is Category 3 or greater on the Saffir–Simpson scale. This was slightly below the average of two per season. Overall, the tropical cyclones of this season collectively caused about $1.68 billion in damage and 76 deaths.

Season activity began with the formation of an unnamed tropical storm over the southern Gulf of Mexico on June 13. There were no other tropical storms in the Atlantic basin until the latter part of August, when hurricanes Anna and Betsy formed. The latter developed on August 27 and eventually became the most intense tropical cyclone of the 1965 season, peaking as a Category 4 hurricane with maximum sustained winds of 140 mph (225 km/h) on September 2. While Betsy would mostly exist in September, the month also featured four additional tropical cyclones – an unnamed tropical storm, Hurricane Carol, a tropical depression, and then Debbie. In October, three tropical systems formed, including two unnamed tropical storms and Hurricane Elena. The final tropical cyclone of the 1965 season, an unnamed tropical storm, developed from a previously non-tropical cyclone northeast of the Lesser Antilles on November 29. The storm persisted into the month of December, before dissipating on December 2.

The season's activity was reflected with an accumulated cyclone energy (ACE) rating of 88, which was near the 1950–2005 average of 93.2. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. It is only calculated for full advisories on tropical cyclones with winds exceeding 39 mph (63 km/h), which is tropical storm strength.

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